Patients with acute-on-chronic liver failure (ACLF) represent a heterogeneous population. The aim of the study is to identify distinct groups according to the etiologies of precipitating events. A total of 405 ACLF patients were identified from 1,361 patients with cirrhosis with acute decompensation and categorized according to the types of acute insults. Clinical characteristics and prognosis between the hepatic group and extrahepatic group were compared, and the performance of prognostic models was tested in different groups. Two distinct groups (hepatic-ACLF and extrahepatic-ACLF) were identified among the ACLF population. Hepatic-ACLF was precipitated by hepatic insults and had relatively wellcompensated cirrhosis with frequent liver and coagulation failure. In contrast, extrahepatic-ACLF was exclusively precipitated by extrahepatic insults, characterized by more severe underlying cirrhosis and high occurrence of extrahepatic organ failures (kidney, cerebral, circulation, and respiratory systems). Both groups had comparably high short-term mortality (28-day transplant-free mortality: 48.3% vs. 50.7%; P 5 0.22); however, the extrahepatic-ACLF group had significantly higher 90-day and 1-year mortality (90-day: 58.9% vs. 68.3%, P 5 0.035; 1-year: 63.9% vs. 74.6%, P 5 0.019). In hepatic-ACLF group, the integrated Model for End-Stage Liver Disease (iMELD) score had the highest area under the receiver operating characteristic curve (auROC 5 0.787) among various prognostic models in predicting 28-day mortality, whereas CLIF-Consortium scores for ACLF patients (CLIF-C-ACLF) had the highest predictive value in the other group (auROC 5 0.779). Conclusions: ACLF precipitated by hepatic insults is distinct from ACLF precipitated by extrahepatic insults in clinical presentation and prognosis. The iMELD score may be a better predictor for hepatic-ACLF short-term prognosis, whereas CLIF-C-ACLF may be better for extrahepatic-ACLF patients. (HEPATOLOGY 2015;62:232-242)

The innate immune system recognizes microorganisms through a series of pattern recognition receptors that are highly conserved in evolution. Insects have a family of 12 peptidoglycan recognition proteins (PGRPs) that recognize peptidoglycan, a ubiquitous component of bacterial cell walls. We report cloning of three novel human PGRPs (PGRP-L, PGRP-I␣, and PGRP-I␤) that together with the previously cloned PGRP-S, define a new family of human pattern recognition molecules. PGRP-L, PGRP-I␣, and PGRP-I␤ have 576, 341, and 373 amino acids coded by five, seven, and eight exons on chromosomes 19 and 1, and they all have two predicted transmembrane domains. All mammalian and insect PGRPs have at least three highly conserved C-terminal PGRP domains located either in the extracellular or in the cytoplasmic (or in both) portions of the molecules. PGRP-L is expressed in liver, PGRP-I␣ and PGRP-I␤ in esophagus (and to a lesser extent in tonsils and thymus), and PGRP-S in bone marrow (and to a lesser extent in neutrophils and fetal liver). All four human PGRPs bind peptidoglycan and Grampositive bacteria. Thus, these PGRPs may play a role in recognition of bacteria in these organs.

Biological rhythms are considered to be ubiquitous in eukaryotic and prokaryotic organisms and are synchronized so the organism can adapt to environmental changes. Circadian rhythm is the most common of the biological rhythms and the molecular clock mechanism has been studied extensively. However, no circadian rhythm has been discovered in yeast and instead two kinds of ultradian rhythms of energy metabolism have been reported. One is a KCN-induced oscillation of the glycolytic pathway and the other is an energymetabolism oscillation (EMO) found in aerobic chemostat cultures. The KCN-induced oscillations were evoked after addition of glucose by inhibiting mitochondrial respiration with cyanide [1] and show a periodicity of 1-2 min as monitored by measuring the level of NAD(P)H. The glycolytic pathway has been The energy-metabolism oscillation in aerobic chemostat cultures of yeast is a periodic change of the respiro-fermentative and respiratory phase. In the respiro-fermentative phase, the NADH level was kept high and respiration was suppressed, and glucose was anabolized into trehalose and glycogen at a rate comparable to that of catabolism. On the transition to the respiratory phase, cAMP levels increased triggering the breakdown of storage carbohydrates and the increased influx of glucose into the glycolytic pathway activated production of glycerol and ethanol consuming NADH. The resulting increase in the NAD + ⁄ NADH ratio stimulated respiration in combination with a decrease in the level of ATP, which was consumed mainly in the formation of biomass accompanying budding, and the accumulated ethanol and glycerol were gradually degraded by respiration via NAD + -dependent oxidation to acetate and the respiratory phase ceased after the recovery of NADH and ATP levels. However, the mRNA levels of both synthetic and degradative enzymes of storage carbohydrates were increased around the early respiro-fermentative phase, when storage carbohydrates are being synthesized, suggesting that the synthetic enzymes were expressed directly as active forms while the degradative enzymes were activated late by cAMP. In summary, the energy-metabolism oscillation is basically regulated by a feedback loop of oxido-reductive reactions of energy metabolism mediated by metabolites like NADH and ATP, and is modulated by metabolism of storage carbohydrates in combination of post-translational and transcriptional regulation of the related enzymes. A potential mechanism of energy-metabolism oscillation is proposed.Abbreviations ADH, alcohol dehydrogenase; ALD, aldehyde dehydrogenase; DO, dissolved oxygen; EMO, energy-metabolism oscillation; FBP, fructose-1,6-bisphosphate; F-2,6-BP, fructose-2,6-bisphosphate; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; OUR, oxygen uptake rate; PDC, pyruvate dehydrogenase complex; PKA, protein kinase A.

Bacteria and their ubiquitous cell wall component peptidoglycan (PGN) activate the innate immune system of the host and induce the release of inflammatory molecules. TNF-α is one of the highest induced cytokines in macrophages stimulated with PGN; however, the regulation of tnf-α expression in PGN-activated cells is poorly understood. This study was done to identify some of the transcription factors that regulate the expression of the tnf-α gene in macrophages stimulated with PGN. Our results demonstrated that PGN-induced expression of human tnf-α gene is regulated by sequences proximal to −182 bp of the promoter. Mutations within the binding sites for cAMP response element, early growth response (Egr)-1, and κB3 significantly reduced this induction. The transcription factor c-Jun bound the cAMP response element site, Egr-1 bound the Egr-1 motif, and NF-κB p50 and p65 bound to the κB3 site on the tnf-α promoter. PGN rapidly induced transcription of egr-1 gene and this induction was significantly reduced by specific mutations within the serum response element-1 domain of the egr-1 promoter. PGN also induced phosphorylation and activation of Elk-1, a member of the Ets family of transcription factors. Elk-1 and serum response factor proteins bound the serum response element-1 domain on the egr-1 promoter, and PGN-induced expression of the egr-1 was inhibited by dominant-negative Elk-1. These results indicate that PGN induces activation of the transcription factors Egr-1 and Elk-1, and that PGN-induced expression of tnf-α is directly mediated through the transcription factors c-Jun, Egr-1, and NF-κB, and indirectly through the transcription factor Elk-1.

gC1q-R, a multifunctional protein, was found to bind with the carboxyl-terminal cytoplasmic domain of the ␣ 1B -adrenergic receptor (173 amino acids, amino acids 344 -516) in a yeast two-hybrid screen of a cDNA library prepared from the rat liver. In a series of studies with deletion mutants in this region, the ten arginine-rich amino acids (amino acids 369 -378) were identified as the site of interaction. The interaction was confirmed by specific co-immunoprecipitation of gC1q-R with fulllength ␣ 1B -adrenergic receptors expressed on transfected COS-7 cells, as well as by fluorescence confocal laser scanning microscopy, which showed co-localization of these proteins in intact cells. Interestingly, the ␣ 1B -adrenergic receptors were exclusively localized to the region of the plasma membrane in COS-7 cells that expressed the ␣ 1B -adrenergic receptor alone, whereas gC1q-R was localized in the cytoplasm in COS-7 cells that expressed gC1q-R alone; however, in cells that coexpressed ␣ 1B -adrenergic receptors and gC1q-R, most of the ␣ 1B -adrenergic receptors were co-localized with gC1q-R in the intracellular region, and a remarkable down-regulation of receptor expression was observed. These observations suggest a new role for the previously identified complement regulatory molecule, gC1q-R, in regulating the cellular localization and expression of the ␣ 1B -adrenergic receptors.G protein-coupled receptors interact with several classes of cytoplasmic proteins including heterotrimeric G proteins, kinases, phosphatases, and arrestins, and the binding of cytoplasmic protein with the receptor regulates receptor signaling (1-4). These interactions were first inferred from the functional effects of cytoplasmic proteins on receptor signaling and desensitization and were later confirmed by biochemical observation of the binding of the protein with receptor (5-8). Very recently, however, several unexpected interactions between cytoplasmic proteins and receptors have been observed; for instance, the adrenergic receptor interacts with the ␣-subunit of the eukaryotic initiation factor 2B (9) and with the Na ϩ /H ϩ -exchange regulatory factor (10). These raise the possibility that receptors may interact with other types of cellular proteins that could play unanticipated roles in regulating the function of the receptor.We conducted a search for novel proteins that interact with the ␣ 1B -adrenergic receptor, specifically focusing on the carboxyl-terminal cytoplasmic domain, because mutations within this domain have pleiotropic effects on receptor physiology (11)(12)(13)(14). Using interaction cloning and biochemical techniques, we demonstrate that gC1q-R 1 interacts with ␣ 1B -adrenergic receptors in vitro and in vivo through the specific site and that in cells that co-express ␣ 1B -adrenergic receptors and gC1q-R, the subcellular localization of ␣ 1B -adrenergic receptors is markedly altered and its expression is down-regulated. These results suggest that gC1q-R plays a role in the regulation of the subcellular localization as ...