mTOR-dependent loss of PON1 secretion and antiphospholipid autoantibody production underlie autoimmunity-mediated cirrhosis in transaldolase deficiency.

Transaldolase deficiency predisposes to chronic liver disease progressing from cirrhosis to hepatocellular carcinoma (HCC). Transition from cirrhosis to hepatocarcinogenesis depends on mitochondrial oxidative stress, as controlled by cytosolic aldose metabolism through the pentose phosphate pathway (PPP). Progression to HCC is critically dependent on NADPH depletion and polyol buildup by aldose reductase (AR), while this enzyme protects from carbon trapping in the PPP and growth restriction in TAL deficiency. Although AR inactivation blocked susceptibility to hepatocarcinogenesis, it enhanced growth restriction, carbon trapping in the non-oxidative branch of the PPP and failed to reverse the depletion of glucose 6-phosphate (G6P) and liver cirrhosis. Here, we show that inactivation of the TAL-AR axis results in metabolic stress characterized by reduced mitophagy, enhanced overall autophagy, activation of the mechanistic target of rapamycin (mTOR), diminished glycosylation and secretion of paraoxonase 1 (PON1), production of antiphospholipid autoantibodies (aPL), loss of CD161+ NK cells, and expansion of CD38+ Ito cells, which are responsive to treatment with rapamycin in vivo. The present study thus identifies glycosylation and secretion of PON1 and aPL production as mTOR-dependent regulatory checkpoints of autoimmunity underlying liver cirrhosis in TAL deficiency.

Cytosolic aldose metabolism contributes to progression from cirrhosis to hepatocarcinogenesis.

Oxidative stress modulates carcinogenesis in the liver; however, direct evidence for metabolic control of oxidative stress during pathogenesis, particularly, of progression from cirrhosis to hepatocellular carcinoma (HCC), has been lacking. Deficiency of transaldolase (TAL), a rate-limiting enzyme of the non-oxidative branch of the pentose phosphate pathway (PPP), restricts growth and predisposes to cirrhosis and HCC in mice and humans. Here, we show that mitochondrial oxidative stress and progression from cirrhosis to HCC and acetaminophen-induced liver necrosis are critically dependent on NADPH depletion and polyol buildup by aldose reductase (AR), while this enzyme protects from carbon trapping in the PPP and growth restriction in TAL deficiency. Both TAL and AR are confined to the cytosol; however, their inactivation distorts mitochondrial redox homeostasis in opposite directions. The results suggest that AR acts as a rheostat of carbon recycling and NADPH output of the PPP with broad implications for disease progression from cirrhosis to HCC.

Analysis of phenolic compounds in the dissolved and suspended phases of Lake Balaton water by gas chromatography-tandem mass spectrometry.

As a novel approach to characterize the phenolic pollutants of Lake Balaton (Central Europe, western Hungary), 26 endocrine disrupting phenols (chlorophenols, nitrophenols, alkylphenols, triclosan, bisphenol-A) were quantified in dissolved and suspended particulate matter (SPM) phases, alike. Sample collection was performed in the western and eastern basins, at 20 sites in April and October 2014. Solid-phase and ultrasound-assisted extractions to withdraw target phenols from dissolved and suspended phases were employed. Compounds were derivatized with hexamethyldisilazane and trifluoroacetic acid for their quantification as trimethylsilyl derivatives by gas chromatography-tandem mass spectrometry. In Lake Balaton's dissolved phase, 2-chlorophenol (103-164 ng/L), 4-chlorophenol (407-888 ng/L), 2,4-dichlorophenol (20.2-72.0 ng/L), 2,4,6-trichlorophenol (10.4-38.1 ng/L), 2-nitrophenol (31.0-66.5 ng/L), 4-nitrophenol (31.5-94.1 ng/L), and bisphenol-A (20.6-112 ng/L), while in its SPM, 4-chlorophenol (

Systematic derivatization, mass fragmentation and acquisition studies in the analysis of chlorophenols, as their silyl derivatives by gas chromatography-mass spectrometry.

An exhaustive GC-MS sample preparation, derivatization, mass fragmentation and acquisition study was performed, for the simultaneous analysis of chlorophenols (CPs). Selected species were 2-CP, 3-CP, 4-CP, 3,5-dichlorophenol (diCP), 2,5-diCP, 2,6-diCP, 2,4-diCP, 2,3-diCP, 3,4-diCP 2,4,6-trichlorophenol (triCP), 2,4,5-triCP, 2,3,4-triCP, 2,3,4,6-tetrachlorophenol (tetraCP) and pentachlorophenol (pentaCP), in total 14 compounds. As novelties to the field, basic researches, like systematic derivatization, mass fragmentation and acquisition methods have been optimized for the trimethylsilyl (TMS) ether derivatives of CPs. The reactivity of chlorophenols with silylating agents has not been systematically analyzed. Here, we studied the reactivity of 14 chlorophenols with five silylating reagents. The three acquisition techniques, the full scan (FS), the multiple ion monitoring (MIM), and the currently optimized multiple reaction monitoring (MRM) methods, have been compared. We developed a new analytical approach, simultaneously monitoring the fragmentation pattern of the (35)Cl and the (37)Cl containing fragment ions both as precursor and as product ions. This principle resulted in remarkable specificity and sensitivity of detection and quantification; particularly in the cases of the tetraCP and pentaCP derivatives containing the (35)Cl and the (37)Cl fragment ions at an approximate ratio of <1:1. Detailed documentation of the loss of HCl via fragmentation processes, without decomposition of the benzene ring, was attributed to the "ring-walk" mechanism described first for monochlorophenol. Critical evaluation of the derivatization and acquisition protocols was collated and validated with the same characteristics. Data of six point calibration along with the corresponding relative standard deviation percentage (RSD%) values, in the line of FS, MIM and MRM methods (r(2): 0.9987, 0.9992, 0.9989; RSD%: 8.7, 5.6, 8.1), proved to be independent on the acquisition processes. The practical utility of the optimized MRM acquisition techniques was confirmed by the quantitation of the CP contents of Danube River, tap water and distilled water samples. Results confirmed at the first time the primary importance of the MRM acquisition method, even in comparison to the MIM one: we revealed that distilled water contains higher chlorophenol content than tap water, which might have a great significance for the water industry.