Peroxisome targeting signal type 1 (PTS1) receptor is involved in import of both PTS1 and PTS2: studies with PEX5-defective CHO cell mutants

To investigate the mechanisms of peroxisome assembly and the molecular basis of peroxisome assembly disorders, we isolated and characterized a peroxisome-deficient CHO cell mutant, ZP139, which was found to belong to human complementation group II, the same group as that of our earlier mutant, ZP105. These mutants had a phenotypic deficiency in the import of peroxisomal targeting signal type 1 (PTS1) proteins. Amino-terminal extension signal (PTS2)-mediated transport, including that of 3-ketoacyl coenzyme A thiolase, was also defective in ZP105 but not in ZP139. PEX5 cDNA, encoding the PTS1 receptor (PTS1R), was isolated from wild-type CHO-K1 cells. PTS1R's deduced primary sequence comprised 595 amino acids, 7 amino acids less than the human homolog, and contained seven tetratricopeptide repeat (TPR) motifs at the C-terminal region. Chinese hamster PTS1R showed 94, 28, and 24% amino acid identity with PTS1Rs from humans, Pichia pastoris, and Saccharomyces cerevisiae, respectively. A PTS1R isoform (PTS1RL) with 632 amino acid residues was identified in CHO cells; for PTS1R, 37 amino acids were inserted between residues at positions 215 and 216 of a shorter isoform (PTS1RS). Southern blot analysis of CHO cell genomic DNA suggested that these two isoforms are derived from a single gene. Both types of PEX5 complemented impaired import of PTS1 in mutants ZP105 and ZP139. PTS2 import in ZP105 was rescued only by PTS1RL. This finding strongly suggests that PTS1RL is also involved in the transport of PTS2. Mutations in PEX5 were determined by reverse transcription-PCR: a G-to-A transition resulted in one amino acid substitution: Gly298Glu of PTS1RS (G335E of PTS1RL) in ZP105 and Gly485Glu of PTS1RS (G522E of PTS1RL) in ZP139. Both mutations were in the TPR domains (TPR1 and TPR6), suggesting the functional consequence of these domains in protein translocation. The implications of these mutations are discussed.

The peroxin Pex14p. cDNA cloning by functional complementation on a Chinese hamster ovary cell mutant, characterization, and functional analysis

Rat cDNA encoding a 376-amino acid peroxin was isolated by functional complementation of a peroxisome-deficient Chinese hamster ovary cell mutant, ZP110, of complementation group 14 (CG14). The primary sequence showed 28 and 24% amino acid identity with the yeast Pex14p from Hansenula polymorpha and Saccharomyces cerevisiae, respectively; therefore, we termed this cDNA rat PEX14 (RnPEX14). Human and Chinese hamster Pex14p showed 96 and 94% identity to rat Pex14p, except that both Pex14p comprised 377 amino acids. Pex14p was characterized as an integral membrane protein of peroxisomes, exposing its N- and C-terminal parts to the cytosol. Pex14p interacts with both Pex5p and Pex7p, the receptors for peroxisome targeting signal type 1 (PTS1) and PTS2, respectively, together with the receptors' cargoes, PTS1 and PTS2 proteins. Mutation in PEX14 from ZP161, the same CG as ZP110, was determined by reverse transcription-PCR as follows. A 133-base pair deletion at nucleotide residues 37-169 in one allele created a termination codon at 40-42; in addition to this mutation, 103 base pairs were deleted at positions 385-487, resulting in the second termination immediately downstream the second deletion site in the other allele. Neither of these two mutant forms of Pex14p restored peroxisome biogenesis in ZP110 and ZP161, thereby demonstrating PEX14 to be responsible for peroxisome deficiency in CG14.

The peroxin pex3p initiates membrane assembly in peroxisome biogenesis

Rat cDNA encoding a 372-amino-acid peroxin was isolated, primarily by functional complementation screening, using a peroxisome-deficient Chinese hamster ovary cell mutant, ZPG208, of complementation group 17. The deduced primary sequence showed approximately 25% amino acid identity with the yeast Pex3p, thereby we termed this cDNA rat PEX3 (RnPEX3). Human and Chinese hamster Pex3p showed 96 and 94% identity to rat Pex3p and had 373 amino acids. Pex3p was characterized as an integral membrane protein of peroxisomes, exposing its N- and C-terminal parts to the cytosol. A homozygous, inactivating missense mutation, G to A at position413, in a codon (GGA) for Gly(138) and resulting in a codon (GAA) for Glu was the genetic cause of peroxisome deficiency of complementation group 17 ZPG208. The peroxisome-restoring activity apparently required the full length of Pex3p, whereas its N-terminal part from residues 1 to 40 was sufficient to target a fusion protein to peroxisomes. We also demonstrated that Pex3p binds the farnesylated peroxisomal membrane protein Pex19p. Moreover, upon expression of PEX3 in ZPG208, peroxisomal membrane vesicles were assembled before the import of soluble proteins such as PTS2-tagged green fluorescent protein. Thus, Pex3p assembles membrane vesicles before the matrix proteins are translocated.

Molecular anatomy of the peroxin Pex12p: ring finger domain is essential for Pex12p function and interacts with the peroxisome-targeting signal type 1-receptor Pex5p and a ring peroxin, Pex10p

The three peroxin genes, PEX12, PEX2, and PEX10, encode peroxisomal integral membrane proteins with RING finger at the C-terminal part and are responsible for human peroxisome biogenesis disorders. Mutation analysis in PEX12 of Chinese hamster ovary cell mutants revealed a homozygous nonsense mutation at residue Trp263Ter in ZP104 cells and a pair of heterozygous nonsense mutations, Trp170Ter and Trp114Ter, in ZP109. This result and domain mapping of Pex12p showed that RING finger is essential for peroxisome-restoring activity of Pex12p but not necessary for targeting to peroxisomes. The N-terminal region of Pex12p, including amino acid residues at positions 17-76, was required for localization to peroxisomes, while the sequence 17-76 was not sufficient for peroxisomal targeting. Peroxins interacting with RING finger of Pex2p, Pex10p, and Pex12p were investigated by yeast two-hybrid as well as in vitro binding assays. The RING finger of Pex12p bound to Pex10p and the PTS1-receptor Pex5p. Pex10p also interacted with Pex2p and Pex5p in vitro. Moreover, Pex12p was co-immunoprecipitated with Pex10p from CHO-K1 cells, where Pex5p was not associated with the Pex12p-Pex10p complex. This observation suggested that Pex5p does not bind to, or only transiently interacts with, Pex10p and Pex12p when Pex10p and Pex12p are in the oligomeric complex in peroxisome membranes. Hence, the RING finger peroxins are most likely to be involved in Pex5p-mediated matrix protein import into peroxisomes.

PEX12, the pathogenic gene of group III Zellweger syndrome: cDNA cloning by functional complementation on a CHO cell mutant, patient analysis, and characterization of PEX12p

Rat PEX12 cDNA was isolated by functional complementation of peroxisome deficiency of a mutant CHO cell line, ZP109 (K. Okumoto, A. Bogaki, K. Tateishi, T. Tsukamoto, T. Osumi, N. Shimozawa, Y. Suzuki, T. Orii, and Y. Fujiki, Exp. Cell Res. 233:11-20, 1997), using a transient transfection assay and an ectopic, readily visible marker, green fluorescent protein. This cDNA encodes a 359-amino-acid membrane protein of peroxisomes with two transmembrane segments and a cysteine-rich zinc finger, the RING motif. A stable transformant of ZP109 with the PEX12 was morphologically and biochemically restored for peroxisome biogenesis. Pex12p was shown by expression of bona fide as well as epitope-tagged Pex12p to expose both N- and C-terminal regions to the cytosol. Fibroblasts derived from patients with the peroxisome deficiency Zellweger syndrome of complementation group III (CG-III) were also complemented for peroxisome biogenesis with PEX12. Two unrelated patients of this group manifesting peroxisome deficiency disorders possessed homozygous, inactivating PEX12 mutations: in one, Arg180Thr by one point mutation, and in the other, deletion of two nucleotides in codons for 291Asn and 292Ser, creating an apparently unchanged codon for Asn and a codon 292 for termination. These results indicate that the gene encoding peroxisome assembly factor Pex12p is a pathogenic gene of CG-III peroxisome deficiency. Moreover, truncation and site mutation studies, including patient PEX12 analysis, demonstrated that the cytoplasmically oriented N- and C-terminal parts of Pex12p are essential for biological function.

Human PEX1 cloned by functional complementation on a CHO cell mutant is responsible for peroxisome-deficient Zellweger syndrome of complementation group I

The peroxisome biogenesis disorders (PBDs), including Zellweger syndrome (ZS) and neonatal adrenoleukodystrophy (NALD), are autosomal recessive diseases caused by defects in peroxisome assembly, for which at least 10 complementation groups have been reported. We have isolated a human PEX1 cDNA (HsPEX1) by functional complementation of peroxisome deficiency of a mutant Chinese hamster ovary (CHO) cell line, ZP107, transformed with peroxisome targeting signal type 1-tagged "enhanced" green fluorescent protein. This cDNA encodes a hydrophilic protein (Pex1p) comprising 1,283 amino acids, with high homology to the AAA-type ATPase family. A stable transformant of ZP107 with HsPEX1 was morphologically and biochemically restored for peroxisome biogenesis. HsPEX1 expression restored peroxisomal protein import in fibroblasts from three patients with ZS and NALD of complementation group I (CG-I), which is the highest-incidence PBD. A CG-I ZS patient (PBDE-04) possessed compound heterozygous, inactivating mutations: a missense point mutation resulting in Leu-664 --> Pro and a deletion of the sequence from Gly-634 to His-690 presumably caused by missplicing (splice site mutation). Both PBDE-04 PEX1 cDNAs were defective in peroxisome-restoring activity when expressed in the patient fibroblasts as well as in ZP107 cells. These results demonstrate that PEX1 is the causative gene for CG-I peroxisomal disorders.

Mutations in PEX10 is the cause of Zellweger peroxisome deficiency syndrome of complementation group B

Peroxisome biogenesis disorders (PBD), such as Zellweger syndrome, are autosomal recessive diseases caused by a deficiency in peroxisome assembly as well as a malfunction of the peroxisomes, where at least 10 genotypes have been reported. We have isolated a human PEX10 cDNA (HsPEX10) by an expressed sequence tag homology search on a human DNA database using yeast PEX10 from Hansenula polymorpha, followed by screening of a human liver cDNA library. This cDNA encodes a peroxisomal protein (a peroxin Pex10p) comprising 326 amino acids, with two putative transmembrane segments and a C3HC4zinc finger RING motif. Both the N- and C-terminal regions of Pex10p are exposed to the cytosol, as assessed by an expression study of epitope-tagged Pex10p. HsPEX10 expression morphologically and biochemically restored peroxisome biogenesis in fibroblasts from Zellweger patients of complementation group B in Japan (complementation group VII in the USA). One patient (PBDB-01) possessed a homozygous, inactivating mutation, a 2 bp deletion immediately upstream of the RING motif, which resulted in a frameshift, altering 65 amino acids from the normal. This implies that the C-terminal part, including the RING finger, is required for biological function of Pex10p. PEX10 cDNA derived from patient PBDB-01 was defective in peroxisome-restoring activity when expressed in patient fibroblasts. These results demonstrate that mutation in PEX10 is the genetic cause of complementation group B PBD.

Possible contribution of circulating transforming growth factor-beta1 to immunity and prognosis in unresectable hepatocellular carcinoma

Transforming growth factor-beta1 (TGF-beta1) has been implicated in tumor progression. The relationship of this cytokine as measured in plasma to anti-tumor immunity and prognosis was investigated. This study consisted of 70 consecutive patients with unresectable hepatocellular carcinoma (HCC) (median age, 65 years). Forty-four healthy age-matched subjects and 32 patients with cirrhosis but no carcinoma served as controls. Patients with HCC were divided into those with plasma TGF-beta1 concentrations above (group A, n=21) or below (group B, n=49) 10 ng/ml (the mean concentration+2SD in the concentrations of the controls with cirrhosis was 8.7 ng/ml). Age, gender, Child-Pugh grade, and tumor stage distributions were similar in groups A and B. Considering all tumor stages together and individually, group A had a significantly shorter survival (median for all stages, 2 months) than group B (median for all stages, 10 months; P<0.01, generalized Wilcoxon's test). Groups A and B had significantly shorter survival than controls with cirrhosis (P<0.001 for each). Lymphokine-activated killer (LAK) activity in group A was significantly lower than that in group B (P<0.001). Natural killer (NK) activity in group A was also significantly lower than that in group B (P<0.05). Plasma TGF-beta1 concentration was a significant predictor of survival by Cox's proportional-hazards regression analysis (multivariate analysis, P<0.01). LAK and NK activities were also weak but significant predictors (P<0.05 and <0.05, respectively). These data suggest that plasma TGF-beta1 concentration is a predictor of outcome of patients with unresectable HCC. Circulating TGF-beta1 supposedly contributes to the suppression of anti-tumor immunity in the advanced disease.

Differentiation of bone marrow cells into cells that express liver-specific genes in vitro: implication of the Notch signals in differentiation

Bone marrow (BM) stem cells have been shown to differentiate into liver cells. It remains difficult to sort and culture BM stem cells, and the gene expression of liver-specific proteins in these cells has not been fully investigated. We used a negative selective magnetic cell separation system to obtain stem cell-enriched BM cells. The cells obtained were cultured with hepatocytes or with hepatocyte growth factor (HGF), and the differentiation of BM cells into cells expressing liver-specific genes, hepatocyte nuclear factor (HNF) 1alpha, cytokeratin (CK) 8, alpha-fetoprotein (AFP), and albumin was investigated by the reverse transcription-polymerase chain reaction. We also investigated the gene expressions of Notch receptor-1 (Notch-1) and its ligand Jagged-1 in BM cell differentiation. Sorted BM cells showed positive for Sca-1 (Ataxin-1) by immunofluorescence staining. Fluorescence activated cell sorter analysis showed that 32.6% of sorted BM cells had a high level of expression of the hematopoietic stem cell marker CD90 (Thy-1). When cultured with hepatocytes, these cells expressed the liver-specific genes HNF1alpha and CK8 on culture day 3, AFP and albumin on culture day 7. When cultured with HGF (20ng/ml), the cells expressed HNF1alpha on day 3 and CK8 on day 7. Gene expressions of Notch-1 and Jagged-1 were detected in cultured BM cells on day 3. These results suggest that the negative selective magnetic cell separation system is useful for the rapid preparation of stem cell-enriched BM cells, and that the Notch signaling pathway plays a role in BM cell differentiation into a hepatocyte lineage in vitro.

Potential therapeutic application of intravenous autologous bone marrow infusion in patients with alcoholic liver cirrhosis

The present study was conducted to evaluate the application and efficacy of autologous bone marrow infusion (ABMi) for improvement of liver function in patients with alcoholic liver cirrhosis (ALC). Five subjects and 5 control patients with ALC who had abstained from alcohol intake for 24 weeks before the study were enrolled. Autologous bone marrow cells were washed and injected intravenously, and the changes in serum liver function parameters, and the level of the type IV collagen 7S domain as a marker of fibrosis, were monitored for 24 weeks. The distribution of activated bone marrow was assessed by indium-111-chloride bone marrow scintigraphy. The number of cells infused was 8.0±7.3×10(9) (mean±standard error). The serum levels of albumin and total protein and the prothrombin time were significantly higher during the follow-up period after ABMi than during the observation period in treated patients, whereas no such changes were observed in the controls. In the patients who received ABMi, the Child-Pugh score decreased in all 3 who were classified as class B; the serum levels of type IV collagen 7S domain improved in 4 of the 5 patients; and bone marrow scintigraphy demonstrated an increase of indium-111-chloride uptake in 3 of the 4 patients tested. ABMi for patients with ALC helps improve liver function parameters in comparison with observation during abstinence and ameliorates the degree of fibrosis in terms of serum markers and bone marrow activation in most cases.

Clofibrate-inducible, 28-kDa peroxisomal integral membrane protein is encoded by PEX11

We cloned a human PEX11 cDNA by expressed sequence tag homology search using yeast Candida boidinii PEX11, followed by screening of human liver cDNA library. PEX11 encoded a peroxisomal protein Pex11p comprising 247 amino acids, with two transmembrane segments and a dilysine motif at the C-terminus. Pex11p comigrated in SDS-PAGE with a 28-kDa peroxisomal integral membrane protein (PMP28) isolated from the liver of clofibrate-treated rats and was crossreactive to anti-PMP28 antibody, thereby indicating PEX11 to encode PMP28. Pex11p exposes both N- and C-terminal parts to the cytosol. PEX11 was not responsible for ten complementation groups of human peroxisome deficiency disorders.

Newly identified Chinese hamster ovary cell mutants are defective in biogenesis of peroxisomal membrane vesicles (Peroxisomal ghosts), representing a novel complementation group in mammals

We isolated peroxisome biogenesis-defective mutants from Chinese hamster ovary cells by the 9-(1'-pyrene)nonanol/ultraviolet (P9OH/UV) method. Seven cell mutants, ZP116, ZP119, ZP160, ZP161, ZP162, ZP164, and ZP165, of 11 P9OH/UV-resistant cell clones showed cytosolic localization of catalase, a peroxisomal matrix enzyme, apparently indicating a defect of peroxisome biogenesis. By transfection of PEX cDNAs and cell fusion analysis, mutants ZP119 and ZP165 were found to belong to a novel complementation group (CG), distinct from earlier mutants. CG analysis by cell fusion with fibroblasts from patients with peroxisome biogenesis disorders such as Zellweger syndrome indicated that ZP119 and ZP165 were in the same CG as the most recently identified human CG-J. The peroxisomal matrix proteins examined, including PTS1 proteins as well as a PTS2 protein, 3-ketoacyl-CoA thiolase, were also found in the cytosol in ZP119 and ZP165. Furthermore, these mutants showed typical peroxisome assembly-defective phenotype such as severe loss of resistance to 12-(1'-pyrene)dodecanoic acid/UV treatment. Most strikingly, peroxisomal reminiscent vesicular structures, so-called peroxisomal ghosts noted in all CGs of earlier Chinese hamster ovary cell mutants as well as in eight CGs of patients' fibroblasts, were not discernible in ZP119 and ZP165, despite normal synthesis of peroxisomal membrane proteins. Accordingly, ZP119 and ZP165 are the first cell mutants defective in import of both soluble and membrane proteins, representing the 14th peroxisome-deficient CG in mammals, including humans.

Fingertip reconstructions using partial-toe transfers

Fifty-six partial toes were transferred to reconstruct fingertip deficits. The transfers from the big toe mainly consisted of 3 trimmed big toetips, 3 vascularized nail grafts, 3 onychocutaneous flaps, 19 thin osteo-onychocutaneous flaps, and 2 hemipulp flaps. The transfers from the second toe mainly consisted of 8 trimmed second toetips, 5 reduced second toes, and 9 whole distal phalanges. The average values of postoperative sensory recovery of the osteo-onychocutaneous flaps including the vascularized nail grafts were 3.1 (Semmes-Weinstein test) and 6.3 mm (moving two-point discrimination) at 2.6 years after the transfer; those of the thin osteo-onychocutaneous flaps were 3.1 and 7.2 mm at 2.0 years after surgery; those of the trimmed big toe tip transfers were 3.61 and 6.5 mm at 1.8 years after surgery; and those of the trimmed second toetip transfers were 3.37 and 6.3 mm at 2.6 years after transfer. Those of the distal phalanx of the second toe were 3.41 and 7.9 mm at 1.2 years after surgery, and those of the reduced second toe were 3.2 and 6.7 mm at 10.6 months after surgery.

Spontaneous elimination of serum hepatitis C virus (HCV) RNA in chronic HCV carriers: a population-based cohort study

The natural course of hepatitis C virus (HCV) infection has not been fully elucidated. To investigate whether HCV is spontaneously eliminated in chronic carriers, a long-term population-based cohort study was conducted on 435 chronic HCV carriers. Individual characteristics, serum HCV RNA, and liver function tests were analyzed, and ultra sonography (US) was performed in all subjects. Subjects were followed up for 7.2 +/- 2.4 years (mean +/- SD). Serum HCV RNA was spontaneously eliminated in 16/435 (3.7%) individuals during this period; thus, the incidence of spontaneous elimination of serum HCV RNA was 0.5%/year/person. Multivariate analysis revealed that both a low value of ZTT and no US finding of chronic liver disease were associated with spontaneous viral elimination in HCV carriers. Three of these 16 individuals had chronic hepatitis, and 13 of them had normal ALT levels. When the neutralization of binding (NOB) assay that evaluates inhibition of the HCV envelope-2 protein binding to human cells was examined using sera from these 16 individuals, the NOB antibody was detected in only 3 cases with chronic hepatitis. These results suggest that serum HCV RNA is spontaneously eliminated in chronic HCV carriers in a population, and that the development of NOB antibody is associated with a natural resolution of chronic hepatitis in the minority of them.

Possible contribution of circulating interleukin-10 (IL-10) to anti-tumor immunity and prognosis in patients with unresectable hepatocellular carcinoma

OBJECTIVES: Interleukin-10 (IL-10) has been implicated in immune deficiency in patients with cancer. The relationship of this cytokine as measured in serum to anti-tumor immunity and prognosis was investigated in unresectable hepatocellular carcinoma. METHODS: This study consisted of 74 consecutive patients with unresectable hepatocellular carcinoma (median age, 65 years). Forty-four healthy age-matched subjects and 32 patients with cirrhosis but no carcinoma served as controls. Patients with hepatocellular carcinoma were divided into those with serum IL-10 concentrations above (high group, n=39) or below (low group, n=35) 10pg/ml. RESULTS: Age, gender, Child-Pugh grade, and tumor stage distributions were similar in high and low groups. The patients of high group showed lower in lymphokine-activated killer (LAK) and natural killer (NK) activities than those of low group (P<0.01 and 0.01, respectively). Serum IL-10 concentration was a significant factor contributing to low activities of LAK and NK by logistic regression analysis (P<0.05 and 0.05, respectively). The high group had a significantly shorter survival (median, 3 months) than low group (median, 12 months; P<0.02, generalized Wilcoxon test). CONCLUSIONS: These data suggest that serum IL-10 concentration is a possible factor contributing to poor prognosis and low anti-tumor immunity in patients with unresectable hepatocellular carcinoma.

Genetic variations in humans associated with differences in the course of hepatitis C

The outcome of hepatitis C virus (HCV) infection varies among individuals, but the genetic factors involved remain unknown. We conducted a population-based association study in which 238 Japanese individuals positive for anti-HCV antibody were genotyped for 269 single nucleotide polymorphisms (SNPs) in 103 candidate genes that might influence the course of infection. Altogether, 50 SNPs in 32 genes were listed. Genetic polymorphisms in IL4, IL8RB, IL10RA, PRL, ADA, NFKB1, GRAP2, CABIN1, IFNAR2, IFI27, IFI41, TNFRSF1A, ALDOB, AP1B1, SULT2B1, EGF, EGFR, TGFB1, LTBP2, and CD4 were associated with persistent viremia (P < 0.05), whereas those in IL1B, IL1RL1, IL2RB, IL12RB1, IL18R1, STAT5A, GRAP2, CABIN1, IFNAR1, Mx1, BMP8, FGL1, LTBP2, CD34, and CD80 were associated with different serum alanine aminotransferase levels in HCV carriers (P < 0.05). The sorted genes allow us to draw novel hypotheses for future studies of HCV infection to ultimately identify bona fide genes and their variations.

Isolation and characterization of peroxisome-deficient Chinese hamster ovary cell mutants representing human complementation group III

We made use of the 9-(1'-pyrene)nonanol/ultraviolet (P9OH/UV) method and isolated peroxisome-deficient mutant cells. TKa cells, the wild-type Chinese hamster ovary (CHO) cells, CHO-K1, that had been stably transfected with cDNA encoding Pex2p (formerly peroxisome assembly factor-1, PAF-1) were used to avoid frequent isolation of the Z65-type, PEX2-defective mutants. P9OH/UV-resistant cell colonies were examined for the intracellular location of catalase, a peroxisomal matrix enzyme, by immunofluorescence microscopy and using anti-catalase antibody. As six mutant cell clones showed cytosolic catalase, there was likely to be a deficiency in peroxisome assembly. These mutants also showed the typical peroxisome assembly-defective phenotype, including significant decrease of dihydroxyacetonephosphate acyltransferase, the first step key enzyme in plasmalogen synthesis, and loss of resistance to 12-(1'-pyrene)dodecanoic acid/UV treatment. By transfection of Pex2p and Pex6p (formerly PAF-2) cDNAs and cell fusion analysis between the CHO cell mutants, two mutants, ZP104 and ZP109, were found to belong to a novel complementation group. Further complementation analysis using fibroblasts from patients with peroxisome biogenesis disorders revealed that the mutants belonged to human complementation group III. Taken together, ZP104 and ZP109 are in a newly identified fifth complementation group in CHO mutants reported to date and represent the human complementation group III.

Isolation of a new peroxisome-deficient CHO cell mutant defective in peroxisome targeting signal-1 receptor

For the study of mechanism of peroxisome biogenesis, we attempted to isolate CHO cell mutants deficient in peroxisome biogenesis. We used as the parent strain a stable CHO transformant of rat PEX2 (formerly named peroxisome assembly factor-1) cDNA, to avoid unusually frequent isolation of Pex2 mutants. Among the three peroxisome-deficient mutants obtained, ZP102 was a new CHO mutant of complementation group 2, and was restored for peroxisome assembly by the transfection of human PEX5 (formerly called PXR1 or PTS1R) cDNA. This approach would facilitate the isolation of new complementation gorups of peroxisome-deficient CHO mutants and the identification of essential genes for peroxisome biogenesis.

Isolation and characterization of novel peroxisome biogenesis-defective Chinese hamster ovary cell mutants using green fluorescent protein

We developed an improved method for isolation of peroxisome biogenesis-defective somatic animal cell mutants, using a combination of green fluorescent protein (GFP) expression and the 9-(1'-pyrene)nonanol/ultraviolet (P9OH/UV) selection method. We used TKaG1 and TKaG2 cells, the wild-type Chinese hamster ovary (CHO) cells, CHO-K1, that had been stably transfected with cDNAs each encoding rat Pex2p as well as GFP tagged at the C-terminus with peroxisome targeting signal type 1 (PTS1) or N-terminally PTS2-tagged GFP. P9OH/UV-resistant cell colonies were examined for intracellular location of GFP on unfixed cells, by fluorescence microscopy. Seven each of the mutant cell clones isolated from TKaG1 and TKaG2 showed cytosolic GFP-PTS1 and PTS2-GFP, respectively, indicating the defect in peroxisome assembly. By transfection of PEX2, PEX5, PEX6, and PEX12 cDNAs and cell fusion analysis between the CHO cell mutants, five different complementation groups (CGs) were identified. Two mutant clones, ZPG207 and ZPG208, belonged to novel CGs. Further CG analysis using fibroblasts from patients with peroxisome biogenesis disorders, including rhizomelic chondrodysplasia punctata (RCDP), revealed that ZPG208 belonged to none of human CGs. ZPG207 was classified into the same CG as RCDP. Taken together, ZPG208 is in a newly identified, the 12th, CG in peroxisome-deficient CHO mutants reported to date and represents a novel mammalian CG.

Clinical manifestations of liver injury in patients with anorexia nervosa

AIM

The number of Japanese patients with anorexia nervosa (AN) is increasing as society changes. Mild liver injury is a complication of AN in around 30% of cases. In some rare instances, patients present with severe liver injury similar to acute liver failure. However, there are numerous uncertainties over the clinical characteristics of this condition. The objective of the present study was to clarify the clinical characteristics of AN complicated by liver injury and to investigate the factors related to hepatic complications.

METHODS

Thirty-seven patients hospitalized at our institution with a diagnosis of AN were enrolled as the study subjects. The study used clinical data obtained at the time of hospitalization. The enrolled patients underwent subgroup analysis and were categorized into three groups: (i) normal alanine aminotransferase (ALT), (ii) moderately elevated ALT, and (iii) highly elevated ALT.

RESULTS

All of the study subjects were female with a median age of 24 years and presenting with marked weight loss (mean body mass index, 13 kg/m(2) ). Thirteen of the subjects had liver injury. We found that patients in the highly elevated ALT group had a significantly high blood urea nitrogen (BUN)/creatinine ratio, and a low blood sugar level.

CONCLUSIONS

Our present findings indicate that AN patients with highly elevated ALT have a severe dehydration. This suggests that dysfunction of hepatic circulation accompanying severe dehydration due to malnutrition may be an important factor in the development of liver injury in AN patients.

Relationship between alcohol consumption and serum adiponectin levels: the Takahata study--a cross-sectional study of a healthy Japanese population

CONTEXT

The relationship between alcohol consumption and serum adiponectin levels has not been fully explored in an Asian population.

OBJECTIVE

Our goal was to determine whether alcohol consumption is associated with a change in adiponectin levels in a healthy Japanese population.

DESIGN

This was a cross-sectional study.

SETTING

Subjects were recruited from participants in a health check-up program.

PARTICIPANTS

This study included 2932 subjects (1306 men and 1626 women).

MAIN OUTCOME MEASURES

The effects of total weekly or daily volume of ethanol intake on serum adiponectin levels were evaluated. In addition, the correlation of clinical traits with serum adiponectin levels was examined. A multivariate regression model was used to control for possible confounding factors.

RESULTS

Alcohol consumption was weakly correlated with decreased serum adiponectin levels in men [Spearman's ordered correlation coefficient (rs=-0.141; P<0.001]; an even weaker correlation was seen in women (rs=-0.055; P=0.025). Multivariate analysis demonstrated that alcohol consumption was independently associated with hypoadiponectinemia.

CONCLUSION

In contrast to reports from the United States and Europe among White and Black subjects, our study demonstrated an inverse association between alcohol intake and serum adiponectin levels in Asian subjects, suggesting ethnic differences in the effects of alcohol consumption on serum adiponectin levels.

Impact of metabolic syndrome on elevated serum alanine aminotransferase levels in the Japanese population

Measurement of the serum alanine aminotransferase (ALT) level is used as an initial test for detection of liver diseases, and recent studies have also highlighted its potential value as a measure of overall health and survival as a marker of an increased risk of metabolic disorder. This study was designed to clarify the prevalence of elevated ALT levels in the Japanese population and to assess factors associated with ALT elevation. The subjects were 2165 individuals aged 40 to 85 years who participated in a Japanese community-based study referred to as the Takahata Study. Serum ALT levels and factors associated with ALT elevation were investigated. Among 2087 subjects who were negative for hepatitis B and C, the rates of elevated ALT greater than 30 U/L in men and greater than 25 U/L in women were 217 (22.7%) of 957 and 239 (21.2%) of 1130, respectively. These ALT cutoff levels had a specificity of more than 80% for exclusion of subjects with none or 1 of 3 metabolic risk factors: hypertension, lipid metabolism abnormality, and hyperglycemia. Multivariate analysis revealed 5 factors with a significant association with ALT elevation in men (n = 957): high gamma-glutamyltranspeptidase, low adiponectin, high low-density lipoprotein cholesterol, high body mass index, and high homeostasis model assessment insulin resistance index. Similarly, 4 factors were significantly associated with ALT elevation in women (n = 1130): high gamma-glutamyltranspeptidase, low adiponectin, high body mass index, and high homeostasis model assessment insulin resistance index. These results suggest that elevated ALT levels in the Japanese population older than 40 years have a strong association with metabolic syndrome-related features including obesity and insulin resistance.

Objective Response by mRECIST to Initial Lenvatinib Therapy Is an Independent Factor Contributing to Deep Response in Hepatocellular Carcinoma Treated with Lenvatinib-Transcatheter Arterial Chemoembolization Sequential Therapy

OBJECTIVE

There is limited information regarding the benefits of Lenvatinib-transcatheter arterial chemoembolization (LEN-TACE) sequential therapy for unresectable hepatocellular carcinoma (u-HCC). We compared the efficacy and safety of LEN-TACE sequential therapy to LEN monotherapy and investigated the factors contributing to the LEN-TACE sequential therapy deep response.

METHODS

We enrolled a multicenter cohort of 247 patients with u-HCC treated with LEN between 2018 and 2020. Propensity score matching identified 63 matching pairs of patients with well-balanced characteristics. We retrospectively compared the clinical outcomes, including overall survival (OS), progression-free survival (PFS), and incidence of adverse events (AEs), between the LEN-TACE and LEN monotherapy groups. Additionally, we evaluated the tumor response, change in albumin-bilirubin (ALBI) score, factors affecting PFS and OS, and independent predictors contributing to the LEN-TACE sequential therapy deep response. In this study, at eight weeks after resumption of LEN after initial TACE, "deep response" was defined as achieving complete response or partial response (PR) on modified Response Evaluation Criteria in Solid Tumors (mRECIST), and at least a 30% decrease in the sum of diameters of target lesions, taking the baseline sum diameters as the reference.

RESULTS

The OS and PFS in the LEN-TACE group were significantly higher than those in the LEN monotherapy group (p = 0.002 and p = 0.037, respectively). The incidence of AEs related to LEN was not significantly different between the two groups. In LEN-TACE sequential therapy, the objective response rate was 61.9%, and the disease control rate was 74.6%, according to the mRECIST criteria. No significant change in the ALBI score was observed during sequential LEN-TACE therapy. Multivariable analyses revealed that deep response was independently associated with the outcome of the initial response to LEN by mRECIST: PR (odds ratio: 5.176, 95% confidence interval: 1.528-17.537, p < 0.001).

CONCLUSIONS

LEN-TACE sequential therapy may provide more clinical benefits than LEN monotherapy in u-HCC patients who responded to initial LEN treatment. Objective response according to mRECIST to initial LEN is an independent factor contributing to LEN-TACE sequential therapy deep response.