Traditional but Not HIV-Related Factors Are Associated with Nonalcoholic Fatty Liver Disease in Asian Patients with HIV-1 Infection

Background

The prevalence and factors associated with nonalcoholic fatty liver disease (NAFLD) are largely unknown in HIV-1 monoinfected patients.

Methods

The present study elucidated the prevalence and factors associated with NAFLD among Asian patients with HIV-1 infection who underwent abdominal ultrasonography between January 2004 and March 2013. Diagnosis of NAFLD was based on the liver to kidney contrast and diffusion in hepatic echogenicity. Uni- and multi-variate logistic regression analyses were applied to estimate factors associated with NAFLD.

Results

435 Asian patients free of chronic hepatitis B or C virus infection and without excessive alcohol intake were analyzed. NAFLD was diagnosed in 135 (31%) patients. Obesity (BMI >30 kg/m²) was evident in 18 (4.1%) patients, and BMI was >25 kg/m² in 103 (24%). Multivariate analysis identified higher BMI (per 1 kg/m² increment, adjusted OR = 1.198; 95% CI, 1.112–1.290; p<0.001), dyslipidemia (adjusted OR = 2.045; 95% CI, 1.183–3.538; p = 0.010), and higher ALT to AST ratio (per 1 increment, adjusted OR = 3.557; 95% CI, 2.129–5.941; p<0.001) as significant factors associated with NAFLD. No HIV-specific variables, including treatment with dideoxynucleoside analogues (didanosine, stavudine, and zalcitabine) and cumulative duration of antiretroviral therapy (ART), were associated with NAFLD.

Conclusions

The incidence of NALFD among Asian patients with HIV-1 infection is similar to that in Western countries. NAFLD was associated with high BMI, dyslipidemia, and high ALT/AST ratio, but not with HIV-related factors. The results highlight the importance of early recognition and management of NAFLD and traditional factors associated with NAFLD for Asian patients with HIV-1 infection.     

C-terminal region of GADD34 regulates eIF2α dephosphorylation and cell proliferation in CHO-K1 cells

GADD34 is a member of a growth arrest and DNA damage (GADD)-inducible gene family. Here, we established a novel Chinese hamster ovary (CHO)-K1-derived cell line, CHO-K1-G34M, which carries a nonsense mutation (termed the Q525X mutation) in the GADD34 gene. The Q525X mutant protein lacks the C-terminal 66 amino acids required for GADD34 to bind to and activate protein phosphatase 1 (PP1). We investigated the effects of GADD34 with or without the Q525X mutation on the phosphorylation status of PP1 target proteins, including the α subunit of eukaryotic initiation factor 2 (eIF2α) and glycogen synthase kinase 3β (GSK3β). CHO-K1-G34M cells had higher levels of eIF2α phosphorylation compared to the control CHO-K1-normal cells both in the presence and absence of endoplasmic reticulum stress. Overexpression of the wild-type GADD34 protein in CHO-K1-normal cells largely reduced eIF2α phosphorylation, while overexpression of the Q525X mutant did not produce similar reductions. Meanwhile, neither wild type nor Q525X mutation of GADD34 affected the GSK3β phosphorylation status. GADD34 also did not affect the canonical Wnt signaling pathway downstream of GSK3β. Cell proliferation rates were higher, while expression levels of the cyclin-dependent kinase inhibitor p21 were lower in CHO-K1-G34M cells compared to the CHO-K1-normal cells. The GADD34 Q525X mutant had a reduced ability to inhibit cell proliferation and enhance p21 expression of the CHO-K1-normal cells compared to the wild-type GADD34 protein. These results suggest that the GADD34 protein C-terminal plays important roles in regulating not only eIF2α dephosphorylation but also cell proliferation in CHO-K1 cells.     

Active establishment of centromeric CENP-A chromatin by RSF complex

Centromeres are chromosomal structures required for equal DNA segregation to daughter cells, comprising specialized nucleosomes containing centromere protein A (CENP-A) histone, which provide the basis for centromeric chromatin assembly. Discovery of centromere protein components is progressing, but knowledge related to their establishment and maintenance remains limited. Previously, using anti-CENP-A native chromatin immunoprecipitation, we isolated the interphase–centromere complex (ICEN). Among ICEN components, subunits of the remodeling and spacing factor (RSF) complex, Rsf-1 and SNF2h proteins, were found. This paper describes the relationship of the RSF complex to centromere structure and function, demonstrating its requirement for maintenance of CENP-A at the centromeric core chromatin in HeLa cells. The RSF complex interacted with CENP-A chromatin in mid-G1. Rsf-1 depletion induced loss of centromeric CENP-A, and purified RSF complex reconstituted and spaced CENP-A nucleosomes in vitro. From these data, we propose the RSF complex as a new factor actively supporting the assembly of CENP-A chromatin.     

Effects of the principal nutrients on lovastatin production by Monascus pilosus

Lovastatin production is dependent on the substrates provided. We investigated how several carbon and nitrogen sources in the medium affect lovastatin production by Monascus pilosus. M. pilosus required a suitable concentration of organic nitrogen peptone for high lovastatin production. As sole carbon source with peptone, although glucose strongly repressed lovastatin production, maltose was responsible for high production. Interestingly, glycerol combined with maltose enhanced lovastatin production, up to 444 mg/l in the most effective case. Moreover, an isolated mutant, in which glucose repression might be relieved, easily produced the highest level of lovastatin, 725 mg/l on glucose-glycerol-peptone medium. These observations indicate that lovastatin production by M. pilosus is regulated by strict glucose repression and that an appropriate release from this repression by optimizing medium composition and/or by a mutation(s) is required for high lovastatin production.     

Delay of coupling caused by excess additives.

Use of excess quantity of additives such as 1-hydroxybenzotriazole, 1-hydroxy-7-azabenzotriazole, or 3,4-dihydro-3-hydroxy-4-oxo-1,2,3-benzotriazine could retard carbodiimide-mediated peptide coupling or aminolysis of the active esters in organic solvents generally employed in peptide chemistry. Solubility test and infrared spectroscopic data suggested that the amine components interacted with the additives to form some aggregates, which were less reactive toward acylation. The use of 0.1 equimolar additives against carboxyl components or carbodiimides was advantageous for rapid and efficient coupling reaction, especially when the carboxyl components were amino acids carrying urethane type N-protecting groups.     

Grandmothers care for orphans in a provisioned troop of Japanese macaques (<Emphasis Type="Italic">Macaca fuscata</Emphasis>)

This study reports cases in which grandmothers and other closely related adult females cared for orphans in the Arashiyama E-troop, a provisioned troop of Japanese macaques (Macaca fuscata). I observed the behavioral patterns of three orphans (aged 1, 2, and 3 years, respectively). The grandmothers cared for two orphans, while three other closely related adult females cared for the rest of the orphans whose grandmothers were absent. These observations differ from those of previous studies that reported that grandmothers were indifferent towards orphans. This intraspecific variation may be attributed to the demographic conditions of the troop in this study, which had only a few related nulliparous adult females, as a result of artificial birth control. In this group, adult females showed decreased fecundity and an increased interbirth interval as they received birth control treatment; thus, in the absence of their own dependent infants, these females may have invested time in the care of related orphans. Although caregiving by grandmothers is believed to be rare or insignificant in primates, this study suggests that grandmothers and other closely related adult females play an important role for orphans in troops with few related adult females.     

Activity-dependent synaptogenesis: regulation by a CaM-kinase kinase/CaM-kinase I/betaPIX signaling complex

Neuronal activity augments maturation of mushroom-shaped spines to form excitatory synapses, thereby strengthening synaptic transmission. We have delineated a Ca(2+)-signaling pathway downstream of the NMDA receptor that stimulates calmodulin-dependent kinase kinase (CaMKK) and CaMKI to promote formation of spines and synapses in hippocampal neurons. CaMKK and CaMKI form a multiprotein signaling complex with the guanine nucleotide exchange factor (GEF) betaPIX and GIT1 that is localized in spines. CaMKI-mediated phosphorylation of Ser516 in betaPIX enhances its GEF activity, resulting in activation of Rac1, an established enhancer of spinogenesis. Suppression of CaMKK or CaMKI by pharmacological inhibitors, dominant-negative (dn) constructs and siRNAs, as well as expression of the betaPIX Ser516Ala mutant, decreases spine formation and mEPSC frequency. Constitutively-active Pak1, a downstream effector of Rac1, rescues spine inhibition by dnCaMKI or betaPIX S516A. This activity-dependent signaling pathway can promote synapse formation during neuronal development and in structural plasticity.     

Molecular and biochemical characterization of D-phosphoglycerate dehydrogenase from Entamoeba histolytica. A unique enteric protozoan parasite that possesses both phosphorylated and nonphosphorylated serine metabolic pathways.

A putative phosphoglycerate dehydrogenase (PGDH), which catalyzes the oxidation of d-phosphoglycerate to 3-phosphohydroxypyruvate in the so-called phosphorylated serine metabolic pathway, from the enteric protozoan parasite Entamoeba histolytica was characterized. The E. histolytica PGDH gene (EhPGDH) encodes a protein of 299 amino acids with a calculated molecular mass of 33.5 kDa and an isoelectric point of 8.11. EhPGDH showed high homology to PGDH from bacteroides and another enteric protozoan ciliate, Entodinium caudatum. EhPGDH lacks both the carboxyl-terminal serine binding domain and the 13-14 amino acid regions containing the conserved Trp139 (of Escherichia coli PGDH) in the nucleotide binding domain shown to be crucial for tetramerization, which are present in other organisms including higher eukaryotes. EhPGDH catalyzed reduction of phosphohydroxypyruvate to phosphoglycerate utilizing NADH and, less efficiently, NADPH; EhPGDH did not utilize 2-oxoglutarate. Kinetic parameters of EhPGDH were similar to those of mammalian PGDH, for example the preference of NADH cofactor, substrate specificities and salt-reversible substrate inhibition. In contrast to PGDH from bacteria, plants and mammals, the EhPGDH protein is present as a homodimer as demonstrated by gel filtration chromatography. The E. histolytica lysate contained PGDH activity of 26 nmol NADH utilized per min per mg of lysate protein in the reverse direction, which consisted 0.2-0.4% of a total soluble protein. Altogether, this parasite represents a unique unicellular protist that possesses both phosphorylated and nonphosphorylated serine metabolic pathways, reinforcing the biological importance of serine metabolism in this organism. Amino acid sequence comparison and phylogenetic analysis of various PGDH sequences showed that E. histolytica forms a highly supported monophyletic group with another enteric protozoa, cilliate E. caudatum, and bacteroides.     

Identification and characterization of a new plasmid carrying genes for degradation of 2,4-dichlorophenoxyacetate from Pseudomonas cepacia CSV90.

Pseudomonas cepacia CSV90 is able to utilize 2,4-dichlorophenoxyacetate (2,4-D) and 2-methyl-4-chlorophenoxyacetate as sole sources of carbon and energy. Mutants of the strain CSV90 which had lost this ability appeared spontaneously on a nonselective medium. The wild-type strain harbored a 90-kb plasmid, pMAB1, whereas 2,4-D-negative mutants either lost the plasmid or had a 70-kb plasmid, pMAB2. The plasmid pMAB2 was found to have undergone a deletion of a 20-kb fragment of pMAB1. The plasmid-free mutants regained the ability to degrade 2,4-D after introduction of purified pMAB1 by electroporation. Cloning in Escherichia coli of a 10-kb BamHI fragment from pMAB1, the region absent in pMAB2, resulted in the expression of the gene tfdC encoding 3,5-dichlorocatechol 1,2-dioxygenase. After subcloning, the tfdC gene was located in a 1.6-kb HindIII fragment. The nucleotide sequence of the tfdC gene and the restriction map of its contiguous region are identical to those of the well-characterized 2,4-D-degradative plasmid pJP4 of Alcaligenes eutrophus, whereas the overall restriction maps of the two plasmids are different. The N-terminal 44-amino-acid sequence of the enzyme purified from the strain CSV90 confirmed the reading frame in the DNA sequence for tfdC and indicated that the initiation codon GUG is read as methionine instead of valine.