Rab41-mediated ESCRT machinery repairs membrane rupture by a bacterial toxin in xenophagy.

Xenophagy, a type of selective autophagy, is a bactericidal membrane trafficking that targets cytosolic bacterial pathogens, but the membrane homeostatic system to cope with bacterial infection in xenophagy is not known. Here, we show that the endosomal sorting complexes required for transport (ESCRT) machinery is needed to maintain homeostasis of xenophagolysosomes damaged by a bacterial toxin, which is regulated through the TOM1L2-Rab41 pathway that recruits AAA-ATPase VPS4. We screened Rab GTPases and identified Rab41 as critical for maintaining the acidification of xenophagolysosomes. Confocal microscopy revealed that ESCRT components were recruited to the entire xenophagolysosome, and this recruitment was inhibited by intrabody expression against bacterial cytolysin, indicating that ESCRT targets xenophagolysosomes in response to a bacterial toxin. Rab41 translocates to damaged autophagic membranes via adaptor protein TOM1L2 and recruits VPS4 to complete ESCRT-mediated membrane repair in a unique GTPase-independent manner. Finally, we demonstrate that the TOM1L2-Rab41 pathway-mediated ESCRT is critical for the efficient clearance of bacteria through xenophagy.

CD44 correlates with longevity and enhances basal ATF6 activity and ER stress resistance.

The naked mole rat (NMR) is the longest-lived rodent, resistant to multiple age-related diseases including neurodegeneration. However, the mechanisms underlying the NMR's resistance to neurodegenerative diseases remain elusive. Here, we isolated oligodendrocyte progenitor cells (OPCs) from NMRs and compared their transcriptome with that of other mammals. Extracellular matrix (ECM) genes best distinguish OPCs of long- and short-lived species. Notably, expression levels of CD44, an ECM-binding protein that has been suggested to contribute to NMR longevity by mediating the effect of hyaluronan (HA), are not only high in OPCs of long-lived species but also positively correlate with longevity in multiple cell types/tissues. We found that CD44 localizes to the endoplasmic reticulum (ER) and enhances basal ATF6 activity. CD44 modifies proteome and membrane properties of the ER and enhances ER stress resistance in a manner dependent on unfolded protein response regulators without the requirement of HA. HA-independent role of CD44 in proteostasis regulation may contribute to mammalian longevity.

Galectin-3 promotes the adipogenic differentiation of PDGFRα+ cells and ectopic fat formation in regenerating muscle.

Worldwide prevalence of obesity is associated with the increase of lifestyle-related diseases. The accumulation of intermuscular adipose tissue (IMAT) is considered a major problem whereby obesity leads to sarcopenia and metabolic disorders and thus is a promising target for treating these pathological conditions. However, whereas obesity-associated IMAT is suggested to originate from PDGFRα+ mesenchymal progenitors, the processes underlying this adipogenesis remain largely unexplored. Here, we comprehensively investigated intra- and extracellular changes associated with these processes using single-cell RNA sequencing and mass spectrometry. Our single-cell RNA sequencing analysis identified a small PDGFRα+ cell population in obese mice directed strongly toward adipogenesis. Proteomic analysis showed that the appearance of this cell population is accompanied by an increase in galectin-3 in interstitial environments, which was found to activate adipogenic PPARγ signals in PDGFRα+ cells. Moreover, IMAT formation during muscle regeneration was significantly suppressed in galectin-3 knockout mice. Our findings, together with these multi-omics datasets, could unravel microenvironmental networks during muscle regeneration highlighting possible therapeutic targets against IMAT formation in obesity.

Priming Phosphorylation of TANK-Binding Kinase 1 by IκB Kinase ß Is Essential in Toll-Like Receptor 3/4 Signaling.

TRIF is an essential adaptor for Toll-like receptor 3/4 (TLR3/4) signaling to activate transcription factor interferon regulatory factor 3 (IRF-3). We examined the molecular mechanism of TLR3 signaling and found that TLR3 stimulation by double-stranded RNA (dsRNA) induces phosphorylation of TRIF at Ser210 and is required for IRF-3 recruitment. TANK-binding kinase 1 (TBK1) is known to be responsible for IRF-3 phosphorylation and activation. We found that TBK1 is also responsible for phosphorylation of Ser210 in TRIF. Unexpectedly, we discovered that IκB kinase ß (IKKß) plays an essential role in TLR3/4 signaling using a pharmacological inhibitor and gene deletion. Of note, IKKß is essential in TLR3/4 but not in retinoic acid-inducible gene I (RIG-I) signaling. Mechanistically, IKKß transiently associates with and induces the phosphorylation of TBK1 upon TLR3 stimulation. These results suggest a phosphorylation cascade of IKKß and TBK1, where priming phosphorylation of TBK1 by IKKß is required to surpass the threshold to induce signaling, thereby activating IRF-3.

The Ratios of monounsaturated to saturated phosphatidylcholines in lung adenocarcinoma microenvironment analyzed by Liquid Chromatography-Mass spectrometry and imaging Mass spectrometry.

Adenocarcinoma is the most common type of lung cancer, and can be classified into various histologic subtypes. However, little is known about the subtype-dependent variations in lipid metabolism processes. We performed dual lipidomic analyses using liquid chromatography-mass spectrometry (LC-MS) and matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) to identify possible biomarkers to distinguish adenocarcinoma specimens from normal lung specimens, and to determine if there are any differences in lipid metabolism among the histologic subtypes (lepidic, acinar, papillary, micropapillary, solid, and mucinous). LC-MS was used to characterize the lipid profiles of lung adenocarcinoma and normal lung tissue, and MALDI-IMS analysis was performed to confirm the results with information on lipid localization within the lung. LC-MS analysis found significant differences in the relative abundances of phosphatidylcholine (PC)(16:0/16:0) (P = 0.0432) and sphingomyelin (SM)(42:2) (P < 0.0001) between adenocarcinoma and normal lung specimens. The ratios of PC(16:0/16:1)/PC(16:0/16:0), PC(16:0/18:1)/PC(16:0/16:0), and PC(16:0/18:1)/PC(16:0/18:0) were significantly higher in adenocarcinoma specimens (P = 0.02221, P = 0.0004, and P = 0.0215, respectively). MALDI-IMS analysis confirmed that these ratios were significantly higher in adenocarcinoma regions of the lung. The ratio of PC(16:0-18:1)/PC(16:0-18:0) was significantly lower in solid subtypes than in other subtypes (P = 0.0028). The monounsaturated/saturated PC ratios may have applications in adenocarcinoma diagnoses and subtyping.

Hepatokine α1-Microglobulin Signaling Exacerbates Inflammation and Disturbs Fibrotic Repair in Mouse Myocardial Infarction.

Acute cardiac rupture and adverse left ventricular (LV) remodeling causing heart failure are serious complications of acute myocardial infarction (MI). While cardio-hepatic interactions have been recognized, their role in MI remains unknown. We treated cultured cardiomyocytes with conditioned media from various cell types and analyzed the media by mass spectrometry to identify α1-microglobulin (AM) as an Akt-activating hepatokine. In mouse MI model, AM protein transiently distributed in the infarct and border zones during the acute phase, reflecting infiltration of AM-bound macrophages. AM stimulation activated Akt, NFκB, and ERK signaling and enhanced inflammation as well as macrophage migration and polarization, while inhibited fibrogenesis-related mRNA expression in cultured macrophages and cardiac fibroblasts. Intramyocardial AM administration exacerbated macrophage infiltration, inflammation, and matrix metalloproteinase 9 mRNA expression in the infarct and border zones, whereas disturbed fibrotic repair, then provoked acute cardiac rupture in MI. Shotgun proteomics and lipid pull-down analysis found that AM partly binds to phosphatidic acid (PA) for its signaling and function. Furthermore, systemic delivery of a selective inhibitor of diacylglycerol kinase α-mediated PA synthesis notably reduced macrophage infiltration, inflammation, matrix metalloproteinase activity, and adverse LV remodeling in MI. Therefore, targeting AM signaling could be a novel pharmacological option to mitigate adverse LV remodeling in MI.

Selective dissociation between LSD1 and GFI1B by a LSD1 inhibitor NCD38 induces the activation of ERG super-enhancer in erythroleukemia cells.

Lysine-specific demethylase 1 (LSD1) is a histone modifier for transcriptional repression involved in the regulation of hematopoiesis. We previously reported that a LSD1 inhibitor NCD38 induces transdifferentiation from erythroid lineage to granulomonocytic lineage and exerts anti-leukemia effect through de-repression of the specific super-enhancers of hematopoietic regulators including ERG in a human erythroleukemia cell line, HEL. However, the mechanistic basis for this specificity of NCD38 has remained unclear. Herein, we report major partners associated with LSD1 and clarify the mechanism in HEL cells. Proteome analysis identified 54 candidate proteins associated with LSD1, including several transcription factors such as GFI1B and RUNX1 as well as BRAF-histone deacetylase complex (BHC) components such as CoREST, HDAC1, and HDAC2. NCD38 selectively disrupted the interaction of LSD1 with GFI1B but not with RUNX1, CoREST, HDAC1 and HDAC2. Erg was downregulated in murine erythroid progenitors with prominent upregulation of Gfi1b. NCD38 induced ERG and attenuated an erythroid marker CD235a in HEL while this attenuation was mimicked by the lentiviral overexpression of ERG. The ERG super-enhancer contained the conserved binding motif of GFI1B and was actually occupied by GFI1B. NCD38 dissociated LSD1 and CoREST but not GFI1B from the ERG super-enhancer. Collectively, the selective separation of LSD1 from GFI1B by NCD38 restores the ERG super-enhancer activation and consequently upregulates ERG expression, inducing the transdifferentiation linked to the anti-leukemia effect.

Anti-carbamylated Protein Antibodies Are Detectable in Various Connective Tissue Diseases.

OBJECTIVE: Anti-carbamylated protein (anti-CarP) antibodies are possible diagnostic biomarkers of anticitrullinated protein antibody (ACPA)-negative rheumatoid arthritis (RA). We aimed to elucidate the prevalence of anti-CarP antibodies in non-RA connective tissue diseases (CTD) because CTD are important in the differential diagnosis of ACPA-negative RA. METHODS: The sera from 266 patients with RA and 616 patients with CTD and 80 healthy controls were examined using an in-house anti-CarP ELISA. RESULTS: The prevalence and the level of anti-CarP antibodies in several CTD were comparable to those in ACPA-negative RA. CONCLUSION: Anti-CarP antibodies are not useful for differentiating ACPA-negative RA from CTD.

Carbamylated albumin is one of the target antigens of anti-carbamylated protein antibodies.

Objectives: Anti-carbamylated protein (anti-CarP) antibodies are detected in RA patients. Fetal calf serum is used as an antigen source in anti-CarP ELISA, and the precise target antigens have not been found. We aimed to identify the target antigens of anti-CarP antibodies. Methods: Western blotting of anti-CarP antibodies was conducted. Anti-carbamylated human albumin (CarALB) antibody was detected by in-house ELISA for 493 RA patients and 144 healthy controls (HCs). An inhibition ELISA of anti-CarP antibodies by CarALB and citrullinated albumin (citALB) was performed using eight RA patients' sera. Serum CarALB was detected by liquid chromatography-tandem mass spectroscopy (LC/MS/MS), and the serum MPO concentration was measured by ELISA. Results: We focused on carbamylated albumin because it corresponded to the size of the thickest band detected by western blotting of anti-CarP antibodies. Anti-CarALB antibody was detected in 31.4% of RA patients, and the correlation of the titres between anti-CarALB and anti-CarP was much closer than that between anti-citALB and anti-CCP antibodies (ρ = 0.59 and ρ = 0.16, respectively). The inhibition ELISA showed that anti-CarP antibodies were inhibited by CarALB, but not by citALB. CarALB was detected in sera from RA patients by LC/MS/MS. The serum MPO concentration was correlated with disease activity and was higher in RA patients with anti-CarALB antibody than in those without. Conclusion: We found that carbamylated albumin is a novel target antigen of anti-CarP antibodies, and it is the first reported target antigen that has not been reported as the target of ACPA.

The cleavage site preference of the porcine pepsin on the N-terminal α1 chain of bovine type I collagen: a focal analysis with mass spectrometry.

Bovine type I collagen consists of two α1 and one α2 chains, containing the internal triple helical regions and the N- and C-terminal telopeptides. In industries, it is frequently digested with porcine pepsin to produce a triple helical collagen without the telopeptides. However, the digestion mechanism is not precisely understood. Here, we performed a mass spectrometric analysis of the pepsin digest of the N-terminal telopeptide pQLSYGYDEKSTGISVP (1-16) in the α1 chain. When purified collagen was digested, pQLSYGY (1-6) and pQLSYGYDEKSTG (1-12) were identified, while DEKSTG (7-12) was not. When the N-terminal telopeptide mimetic synthetic peptide pQLSK(MOCAc)GYDEKSTGISK(Dnp)P-NH2 was digested, pQLSK(MOCAc)GYDEKSTG (1-12) and ISK(Dnp)P-NH2 (13-16) were readily identified, pQLSK(MOCAc)GY (1-6) and DEKSTGISK(Dnp)P-NH2 (7-16) were weakly detected, and DEKSTG (7-12) was hardly identified. These results suggest that pepsin preferentially cleaves Tyr6-Asp7 and less preferentially Gly12-Ile13. They also suggest that the former cleavage requires native collagen structure, while the latter cleavage does not.

Global Landscape and Regulatory Principles of DNA Methylation Reprogramming for Germ Cell Specification by Mouse Pluripotent Stem Cells.

Specification of primordial germ cells (PGCs) activates epigenetic reprogramming for totipotency, the elucidation of which remains a fundamental challenge. Here, we uncover regulatory principles for DNA methylation reprogramming during in vitro PGC specification, in which mouse embryonic stem cells (ESCs) are induced into epiblast-like cells (EpiLCs) and then PGC-like cells (PGCLCs). While ESCs reorganize their methylome to form EpiLCs, PGCLCs essentially dilute the EpiLC methylome at constant, yet different, rates between unique sequence regions and repeats. ESCs form hypomethylated domains around pluripotency regulators for their activation, whereas PGCLCs create demethylation-sensitive domains around developmental regulators by accumulating abundant H3K27me3 for their repression. Loss of PRDM14 globally upregulates methylation and diminishes the hypomethylated domains, but it preserves demethylation-sensitive domains. Notably, female ESCs form hypomethylated lamina-associated domains, while female PGCLCs effectively reverse such states into a more normal configuration. Our findings illuminate the unique orchestration of DNA methylation and histone modification reprogramming during PGC specification.

Kinetic Analysis of the Digestion of Bovine Type I Collagen Telopeptides with Porcine Pepsin.

Collagen is frequently digested using pepsin in industries to produce a triple helical collagen without the N- and C-terminal telopeptides. However, kinetic analysis of this reaction is difficult because several Lys residues in the N- and in the C-terminal telopeptides form covalent bonds, leading to multiple substrates species, and pepsin cleaves collagen at various sites in the N-terminal and in the C-terminal telopeptides, yielding different products. Here we performed kinetic analysis of the digestion of bovine type I collagen with porcine pepsin. The reaction could be monitored by SDS-PAGE by measuring the intensity of the protein bands corresponding to the variant ß11 chain. We obtained kinetic parameters relative to the decrease in the variant ß11 chain upon digestion. At pH 4.0, the Km and kcat values increased with increasing temperature (30 to 65 °C), although the kcat /Km values were stable. Additional cleavage at the helical region was detected at 45 to 65 °C. At 37 °C, the Km and kcat values increased with decreasing pH, and the kcat /Km values at pH 2.1 to 4.5 were stable and higher than those at pH 5.0 and 5.5. No additional cleavage was detected at the examined pH. Thus, the optimal pH and temperatures for selective digestion of collagen telopeptides with pepsin are 2.1 to 4.5 and 30 to 40 °C, respectively. These results suggest that the method might be useful for the kinetic analysis of the digestion of collagen telopeptides with pepsin.

Cholestasis induces reversible accumulation of periplakin in mouse liver.

BACKGROUND: Periplakin (PPL) is a rod-shaped cytolinker protein thought to connect cellular adhesion junctional complexes to cytoskeletal filaments. PPL serves as a structural component of the cornified envelope in the skin and interacts with various types of proteins in cultured cells; its level decreases dramatically during tumorigenic progression in human epithelial tissues. Despite these intriguing observations, the physiological roles of PPL, especially in non-cutaneous tissues, are still largely unknown. Because we observed a marked fluctuation of PPL expression in mouse liver in association with the bile acid receptor farnesoid X receptor (FXR) and cholestasis, we sought to characterize the role of PPL in the liver and determine its contributions to the etiology and pathogenesis of cholestasis. METHODS: Time- and context-dependent expression of PPL in various mouse models of hepatic and renal disorders were examined by immunohistochemistry, western blotting, and quantitative real-time polymerase chain reactions. RESULTS: The hepatic expression of PPL was significantly decreased in Fxr-/- mice. In contrast, the expression was dramatically increased during cholestasis, with massive PPL accumulation observed at the boundaries of hepatocytes in wild-type mice. Interestingly, the hepatic accumulation of PPL resulting from cholestasis was reversible. In addition, similar accumulation of PPL at cellular boundaries was found in epithelial cells around renal tubules upon ureteral obstruction. CONCLUSIONS: PPL may be involved in the temporal accommodation to fluid stasis in different tissues. Further examination of the roles for PPL may lead to the discovery of a novel mechanism for cellular protection by cytolinkers that is applicable to many tissues and in many contexts.

The 5'-untranslated region of the Oryza sativa alcohol dehydrogenase gene functions as a translational enhancer in monocotyledonous plant cells.

The 5'-untranslated region (5'-UTR) functions as a translational enhancer in monocotyledonous plant cells is necessary to express a foreign gene efficiently. Here, we show that the 5'-UTR of the rice alcohol dehydrogenase gene contributes to efficient translation in not only dicotyledonous plant cells, but also in monocotyledonous rice cells.

Dietary phytochemicals regulate whole-body CYP1A1 expression through an arylhydrocarbon receptor nuclear translocator-dependent system in gut.

Cytochrome P450 1A1 (CYP1A1) is one of the most important detoxification enzymes due to its broad substrate specificity and wide distribution throughout the body. On the other hand, CYP1A1 can also produce highly carcinogenic intermediate metabolites through oxidation of polycyclic aromatic hydrocarbons. We describe what we believe to be a novel regulatory system for whole-body CYP1A1 expression by a factor originating in the gut. A mutant mouse was generated in which the arylhydrocarbon receptor nuclear translocator (Arnt) gene is disrupted predominantly in the gut epithelium. Surprisingly, CYP1A1 mRNA expression and enzymatic activities were markedly elevated in almost all non-gut tissues in this mouse line. The induction was even observed in early-stage embryos in pregnant mutant females. Interestingly, the upregulation was CYP1A1 selective and lost upon administration of a synthetic purified diet. Moreover, the increase was recovered by addition of the natural phytochemical indole-3-carbinol to the purified diet. These results suggest that an Arnt-dependent pathway in gut has an important role in regulation of the metabolism of dietary CYP1A1 inducers and whole-body CYP1A1 expression. This machinery might be involved in naturally occurring carcinogenic processes and/or other numerous biological responses mediated by CYP1A1 activity.

Clinical and virological features of non-breakthrough and severe exacerbation due to lamivudine-resistant hepatitis B virus mutants.

Patients who develop YMDD mutant during lamivudine therapy for hepatitis B virus (HBV) infection exhibit various clinical courses. Some patients show normal ALT levels, whereas others develop severe hepatitis exacerbations (SHEs) due to YMDD mutants. We studied 136 patients with YMDD mutant among 362 Japanese adult patients on lamivudine therapy. Clinical and virological features of patients without elevated HBV DNA after emergence of YMDD mutant (non-elevated group) were investigated. Moreover, virological analysis was also performed in patients with SHE due to YMDD mutants. Patients in the non-elevated group were characterized by HBeAg-negative pretreatment, HBeAg loss during therapy, a longer duration from commencement of therapy until emergence of YMDD mutant, and no mixed-type YMDD mutants. Patients with SHE had more substitutions in the reverse transcriptase (rt) region within the polymerase gene at the time of exacerbation than those without SHE, although no specific substitutions were noted. Sequence analysis of full-length HBV genome showed more substitutions in X, rt, and surface proteins in patients with SHE than in those without elevated HBV DNA level. In conclusion, negativity for HBeAg at commencement of therapy or before emergence of YMDD mutant was an important factor among non-elevated group. More substitutions in the rt region and the other proteins may be related to the emergence of severe hepatitis caused by lamivudine-resistant virus.

Impaired negative feedback suppression of bile acid synthesis in mice lacking betaKlotho.

We have generated a line of mutant mouse that lacks betaKlotho, a protein that structurally resembles Klotho. The synthesis and excretion of bile acids were found to be dramatically elevated in these mutants, and the expression of 2 key bile acid synthase genes, cholesterol 7alpha-hydroxylase (Cyp7a1) and sterol 12alpha-hydroxylase (Cyp8b1), was strongly upregulated. Nuclear receptor pathways and the enterohepatic circulation, which regulates bile acid synthesis, seemed to be largely intact; however, bile acid-dependent induction of the small heterodimer partner (SHP) NR0B2, a common negative regulator of Cyp7a1 and Cyp8b1, was significantly attenuated. The expression of Cyp7a1 and Cyp8b1 is known to be repressed by dietary bile acids via both SHP-dependent and -independent regulations. Interestingly, the suppression of Cyp7a1 expression by dietary bile acids was impaired, whereas that of Cyp8b1 expression was not substantially altered in betaklotho mice. Therefore, betaKlotho may stand as a novel contributor to Cyp7a1-selective regulation. Additionally, betaKlotho-knockout mice exhibit resistance to gallstone formation, which suggests the potential future clinical relevance of the betaKlotho system.

Clinical and virological characteristics of untreated patients with chronic hepatitis C who develop serum alanine aminotransferase flare-up.

Among patients with chronic hepatitis C virus (HCV) infection, serum alanine aminotransferase (ALT) rarely increases above 500 IU/L. We examined the clinical and virological features of untreated patients with serum ALT > or = 500 IU/L. One thousand seven hundred and sixty adult patients with chronic HCV infection were followed-up. Among these patients, 22 developed ALT flare-up (M:F=13:9, median age, 50.5 years). We evaluated liver function tests, genotype, and viral titer in these patients and 44 randomly selected age- and sex-matched control without ALT flare-up. In four patients with ALT flare-up, we examined changes in viral loads and sequential changes in amino acid sequences of the core region, hypervariable region 1 (HVR1), and interferon sensitivity determining region (ISDR) before and after ALT flare-up. Multivariate analysis identified genotype 2 as the only significant determinant of ALT flare-up. ALT flare-up occurred in three of four patients without increase in viral load. Several alterations in amino acids were noted in HVR1 before and within 6 months of ALT flare-up. One or two alterations in the core region and many alterations in HVR1 were noted after ALT flare-up in some patients. Genotype 2 is an important factor for ALT flare-up. However, we could not directly relate ALT flare-up to these alterations in amino acids of the core region, HVR1, and ISDR.

Efficacy of lamivudine treatment in Japanese patients with hepatitis B virus-related cirrhosis.

BACKGROUND: Several clinical trials have suggested that lamivudine therapy is effective in patients with hepatitis B virus (HBV)-related cirrhosis. However, there are few studies of lamivudine therapy in Japanese patients with HBV cirrhosis. The aim of this study was to evaluate the efficacy of lamivudine therapy in Japanese patients with cirrhosis, and to evaluate the clinical course after the emergence of YMDD mutants. METHODS: Fifty-four consecutive adult Japanese patients with HBV-related cirrhosis were enrolled and continuously treated with lamivudine, daily for 6-35 months (median, 25 months). Twelve of the 54 patients were hepatitis B envelope antigen (HBeAg)-positive. The clinical courses of 21 of the patients were evaluated using the Child-Pugh-Turcott (CPT) score. RESULTS: Lamivudine suppressed serum HBV-DNA to undetectable levels (<3.7 LGE/ml) in 77.8% of patients at 12 months and in 61.3% at 24 months. Before the emergence of YMDD mutants, clinical improvement, defined as a decrease in the CPT score of 2 points or more, was apparent in 6 of 21 (29%) patients. No change in CPT score was evident in 14 of 21 patients (67%). YMDD mutants emerged in 19 of 54 (35%) patients. The cumulative emergence rates increased each year. The emergence rate of YMDD mutants in patients with HBV cirrhosis was higher than that in patients with chronic hepatitis. After the emergence of YMDD mutants, 3 of 12 (25%) patients with YMDD mutants showed CPT score increases of 2 points or more. CONCLUSIONS: Lamivudine therapy improved the clinical course in some cirrhotic patients. However, in patients with Child's B and C cirrhosis, the emergence of YMDD mutants sometimes led to deterioration of liver function.

Efficacy of 6-month interferon therapy in chronic hepatitis B virus infection in Japan.

BACKGROUND: In Japan, there are few studies of long-term (more than 1 month) interferon (IFN) therapy for chronic hepatitis B (CHB). In this retrospective study, we investigated the efficacy and predictors of response to 6-month IFN therapy. METHODS: We analyzed 66 Japanese patients with CHB who were treated with IFN for 6 months. They comprised patients who were hepatitis B e antigen (HBeAg)-positive (n=45) and -negative (n=21). One (2%), 8 (12%), and 51 (77%) patients were infected with hepatitis B virus (HBV) genotypes A, B, and C, respectively. Responders in patients positive for HBeAg were defined as those who showed normalization of serum alanine aminotransferase (ALT) level, HBeAg loss, and HBV DNA negativity at 6 months after completion of IFN therapy. In patients negative for HBeAg, responders were defined as those patients who showed normalization of ALT level and HBV DNA negativity at the same 6-month time point. RESULTS: Of the 45 patients with HBeAg at the commencement of IFN therapy, 9 (20%) were responders. Young patients, especially those with a high serum ALT level, were significantly more likely to respond to IFN therapy. Of the 21 patients negative for HBeAg, 13 (62%) were responders. There were no significant differences in clinical characteristics between responders and nonresponders among patients negative for HBeAg. Multivariate analyses identified HBeAg negativity and young age as independent factors associated with a positive response to 6-month IFN therapy. However, long-term follow-up of the treated patients showed a fall in the response rate. CONCLUSIONS: The response rate to 6-month IFN therapy among HBeAg-positive patients was low. However, young patients may require long-term IFN therapy.