Distinct and overlapping genomic profiles and antiviral effects of Interferon-λ and -α on HCV-infected and noninfected hepatoma cells.

Recently, several SNPs in the region of the IL28B (IFN-λ) gene have been associated with spontaneous clearance of hepatitis C virus (HCV) and enhanced cure rates for IFN-alfa-based therapies, suggesting a potential correlation between IFN-λ and the ability to clear HCV. To understand the mechanism of IFN-λ's as compared to IFN-α's antiviral activity, we performed a comprehensive analysis of their anti-HCV effects, whole genome transcriptome profiling with validation, and signalling of IFN-α and IFN-λ using J6/JFH-1 and Huh7.5 cells in vitro. IFN-λ and IFN-α exhibited comparable anti-HCV activity and gene expression profiles in Huh7.5 cells. While the majority of genes induced by IFN-α and IFN-λ were similar, IFN-λ exhibits profound, but delayed kinetics of IFN-stimulated genes (ISG) induction, while IFN-α induced more rapid induction of ISGs. Furthermore, the increased induction of ISG expression by IFN-λ correlated with up-regulation of IFN-λ receptor (IL-28RA) expression and more prolonged activation of the Jak-STAT signalling pathway. The findings from our comparative analysis of IFN-α and IFN-λ in HCV-infected and noninfected cells support the clinical use of IFN-λ as a potential alternative to IFN-α in the treatment of chronic hepatitis C.

Amino acid deletion at codon 67 and Thr-to-Gly change at codon 69 of human immunodeficiency virus type 1 reverse transcriptase confer novel drug resistance profiles.

The potential roles of an amino acid deletion at codon 67 (Delta67) and a Thr-to-Gly change at codon 69 (T69G) in the reverse transcriptase of human immunodeficiency virus (HIV) type 1 in drug sensitivity and relative replication fitness were studied. Our results suggest that the Delta67 and T69G changes can be categorized as mutations associated with multidrug resistance. The combination of both mutations with an L74I change (Delta67+T69G/L74I) leads to a novel 3'-azido-3'-deoxythymidine resistance motif and compensates for impaired HIV replication.

Relative replication fitness of a high-level 3'-azido-3'-deoxythymidine-resistant variant of human immunodeficiency virus type 1 possessing an amino acid deletion at codon 67 and a novel substitution (Thr-->Gly) at codon 69.

The combination of an amino acid deletion at codon 67 (delta 67) and Thr-to-Gly change at codon 69 (T69G) in the reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1) is associated with high-level resistance to multiple RT inhibitors. To determine the relative contributions of the delta 67 and T69G mutations on viral fitness, we performed a series of studies of HIV replication using recombinant variants. A high-level 3'-azido-3'-deoxythymidine (AZT)-resistant variant containing delta 67 plus T69G/K70R/L74I/K103N/T215F/K219Q in RT replicated as efficiently as wild-type virus (Wt). In contrast, the construct without delta 67 exhibited impaired replication (23% of growth of Wt). A competitive fitness study failed to reveal any differences in replication rates between the delta 67+T69G/K70R/L74I/K103N/T215F/+ ++K219Q mutant and Wt. Evaluation of proviral DNA sequences over a 3-year period in a patient harboring the multiresistant HIV revealed that the T69G mutation emerged in the context of a D67N/K70R/T215F/K219Q mutant backbone prior to appearance of the delta 67 deletion. To assess the impact of this stepwise accumulation of mutations on viral replication, a series of recombinant variants was constructed and analyzed for replication competence. The T69G mutation was found to confer 2',3'-dideoxyinosine resistance at the expense of fitness. Subsequently, the development of the delta 67 deletion led to a virus with improved replication and high-level AZT resistance.

High-level resistance to 3'-azido-3'-deoxythimidine due to a deletion in the reverse transcriptase gene of human immunodeficiency virus type 1.

A variant of human immunodeficiency virus type 1 (HIV-1) possessing a deletion in the reverse transcriptase (RT) gene at codon 67 was identified in a patient who had failed combination antiretroviral therapy. This deletion initially emerged under the selective pressure of combination therapy with 3'-azido-3'-deoxythymidine (AZT) plus 2',3'-dideoxyinosine. It has persisted for more than 3 years in association with the accumulation of a variety of other well-described drug resistance mutations and an uncharacterized mutation at RT codon 69 (T69G). Phenotypic studies demonstrated that the codon 67 deletion by itself had little effect on AZT sensitivity. However, in the context of the T69G mutation and three other mutations known to be associated with AZT resistance (K70R, T215F, and K219Q), this deletion led to a increase in AZT resistance from 8. 5-fold to 445-fold. A further increase in resistance (up to 1, 813-fold) was observed when two mutations associated with nonnucleoside RT inhibitor resistance (K103N and L74I) were added to the deletion T69G K70R T215F K219Q construct. Hence, these results establish that a deletion at RT codon 67 may be selected for in the presence of antiretroviral therapy and may lead to high-level resistance to AZT.

Drug resistance during indinavir therapy is caused by mutations in the protease gene and in its Gag substrate cleavage sites.

Two different responses to the therapy were observed in a group of patients receiving the protease inhibitor indinavir. In one, suppression of virus replication occurred and has persisted for 90 weeks (bDNA, < 500 human immunodeficiency virus type 1 [HIV-1] RNA copies/ml). In the second group, a rebound in virus levels in plasma followed the initial sharp decline observed at the start of therapy. This was associated with the emergence of drug-resistant variants. Sequence analysis of the protease gene during the course of therapy revealed that in this second group there was a sequential acquisition of protease mutations at amino acids 46, 82, 54, 71, 89, and 90. In the six patients in this group, there was also an identical mutation in the gag p7/p1 gag protease cleavage site. In three of the patients, this change was seen as early as 6 to 10 weeks after the start of therapy. In one patient, a second mutation occurred at the gag p1/p6 cleavage site, but it appeared 18 weeks after the time of appearance of the p7/p1 mutation. Recombinant HIV-1 variants containing two or three mutations in the protease gene were constructed either with mutations at the p7/p1 cleavage site or with wild-type (WT) gag sequences. When recombinant HIV-1-containing protease mutations at 46 and 82 was grown in MT2 cells, there was a 68% reduction in its rate of replication compared to the WT virus. Introduction of an additional mutation at the gag p7/p1 protease cleavage site compensated for the partially defective protease gene. Similarly, rates of replication of viruses with mutations M46L/I, I54V, and V82A in protease were enhanced both in the presence and in the absence of Indinavir when combined with mutations in the gag p7/p1 and the gag p1/p6 cleavage sites. Optimal rates of virus replication require protease cleavage of precursor polyproteins. A mutation in the cleavage site that enhanced the availability of a protein that was rate limiting for virus maturation would confer on that virus a significant growth advantage and may explain the uniform emergence of viruses with alterations at the p7/p1 cleavage site. This is the first report of the emergence of mutations in the gag p7/p1 protease cleavage sites in patients receiving protease therapy and identifies this change as an important determinant of HIV-1 resistance to protease inhibitors in patient populations.

Emergence of protease inhibitor resistance mutations in human immunodeficiency virus type 1 isolates from patients and rapid screening procedure for their detection.

Patient human immunodeficiency virus type 1 (HIV-1) isolates that are resistant to protease inhibitors may contain amino acid substitutions L10I/V, M46L/I, G-48V, L63P, V82A/F/T, I84V, and L90M in the protease gene. Substitutions at positions 82 and/or 90 occur in variants that display high levels of resistance to certain protease inhibitors. Nucleotide substitutions at these two sites also lead to the loss of two HindII restriction enzyme digestion sites, and these changes make possible a rapid procedure for the detection of drug-resistant variants in patients on protease inhibitor therapy. This procedure was used to detect the emergence of mutated viruses at various times after the initiation of therapy with the HIV-1 protease inhibitor indinavir. The method includes viral RNA isolation from plasma and reverse transcription PCR amplification of the protease gene with fluorescence-tagged primers. The PCR product is digested with HindII, the cleavage products are separated on a urea-acrylamide gel in a DNA sequencer, and the extent of cleavage is automatically analyzed with commercially available software. In viruses from 34 blood samples from four patients, mutations leading to an amino acid change at residue 82 appeared as early as 6 weeks after the start of therapy and persisted throughout the course of the study period (48 weeks). Mutations leading to double substitutions at residues 82 and 90 were seen at a lower frequency and appeared later than the change at position 82. The changes detected by restriction enzyme cleavage were confirmed by DNA sequencing of the cloned protease genes by reverse transcription PCR amplification of viral RNA from isolates in plasma. In addition to the changes at positions 82 and 90, we have identified M46L/I, G48V, and I54V substitutions in isolates derived from indinavir-treated patients. HindII analysis of uncloned, PCR-amplified DNA offers a rapid screening procedure for the detection of virus isolates containing mutations at amino acid residues 82 and 90 in the HIV-1 protease gene. By using other restriction enzymes, the same method can be used to detect additional protease drug-resistant variants and is generally applicable for the detection of mutations.

Chromosomal localization of a strain-specific p53-related sequence in rat (Rattus norvegicus).

Strain-specific restriction fragments hybridizing to human p53 gene cDNA, which was detected in only particular strains of inbred rat were revealed by Southern blot hybridization of DNAs of various inbred rat strains. Chromosomal location of the strain-specific fragments was determined on rat chromosome 1 between Kal and Pkc loci by linkage analysis using microsatellite marker loci. The fragments were concluded to be a novel p53-related sequence which is present in particular rat strains and absent from the remaining strains.

Synthetic fibronectin peptides suppress arthritis in rats by interrupting leukocyte adhesion and recruitment.

In an experimental model of arthritis, increased leukocyte adhesion is associated with the evolution of acute and chronic synovial inflammation. Whereas peripheral blood mononuclear cells (PBMC) from control animals bind minimally to fibronectin matrices, PBMC from animals receiving arthropathic doses of bacterial cell walls demonstrate increased integrin mRNA expression and enhanced adhesion. To determine whether this augmented adhesion was causal in the development of synovial pathology, peptides synthesized from several fibronectin domains which inhibited leukocyte adhesion in vitro were administered to arthritic animals either as free peptides or coupled to a carrier molecule. Not only were peptides containing either the RGD or CS-1 cell-binding domains inhibitory to chronic synovial pathology (articular index = 10.5 +/- 0.3 for untreated animals compared to 1.25 +/- 0.25 for RGD and 2.5 +/- 0.7 for CS-1), but three peptides synthesized from the carboxy-terminal 33-kD heparin-binding domain of fibronectin were also found to significantly inhibit leukocyte recruitment and the evolution of arthritis. Based on these data, which are the first to explore the therapeutic potential of heparin-binding fibronectin peptides in chronic inflammation, it appears that antagonism of cellular adhesion and recruitment by fibronectin peptides may provide an important mechanism for modulating the multi-step adhesion process and attenuating aberrant inflammatory responses.

A restriction fragment length polymorphism of a p53-related sequence in rat (Rattus norvegicus).

Polymorphisms of the p53 tumor-suppressor gene and its related sequences were investigated among inbred rat strains. In a series of Southern blot hybridizations using the human p53 cDNA probe with various restriction endonucleases, HindIII digests and PstI digests showed interstrain variation in the length of hybridizing fragments. Distribution of the HindIII variant fragments among 17 inbred rat strains was identical with that of PstI variant fragments. The variant fragments were segregated as codominant alleles in backcross progeny, and the locus for this restriction fragment length polymorphism of the p53-related sequence was found to correspond to a p53-related sequence located on rat chromosome 9.

Localization of a N-ras-related sequence on rat chromosome 1.

Location of the locus for a restriction fragment length polymorphism of N-ras-related sequences (NRAS2) on the rat chromosome 1 was determined by linkage analysis using a microsatellite locus (KAL) and a coat-color locus (C). The recombination frequencies between NRAS2 and C, NRAS2 and KAL, and C and KAL in 57 backcross progeny obtained from crosses of (WKS/Iar x IS/Iar) x WKS/Iar were 7.0 +/- 3.4%, 28 +/- 5.9%, and 23 +/- 5.6%, respectively. The order of the three loci on the rat chromosome 1 was determined as follows: KAL-C-NRAS2.

Identification of inbred rat strains by using DNA fingerprinting method.

DNA fingerprinting method was applied to identify inbred strains of laboratory rats. By Southern blot hybridization with core sequence of minisatellite DNA as a probe, typical hypervariable patterns of DNA fingerprint were obtained in inbred rat strains. The patterns were completely different among 15 rat strains examined, and the patterns of the DNA fingerprint of samples obtained from the same strain were completely identical. The patterns of the DNA fingerprint of two substrains derived from the same strain were identical, indicating relative stability of the patterns over a large number of generations. Therefore, we concluded that the DNA fingerprinting method was useful for the identification of inbred strains in genetic monitoring of laboratory rats.

Characterization of C3a anaphylatoxin receptor on guinea-pig macrophages.

We have characterized a C3a receptor on guinea-pig macrophages by 125I-C3a binding and functional responses. Scatchard analysis applied to the 125I-C3a binding to guinea-pig macrophages revealed the existence of two receptor classes; a high-affinity class with approximately 0.63 x 10(5) binding sites/cell with a Kd = 2.7 nM, and a relatively low-affinity class with approximately 1.2 x 10(5) binding sites/cell with a Kd = 51 nM. The binding of C3a to macrophages was totally blocked when there was an excess of C3a. C3a triggered a transient intracellular Ca2+ ([Ca2+]i) mobilization in macrophages, which was accompanied by homologous desensitization. C3a was also capable of generating O2- from macrophages. The C3a-induced Ca2+ response and O2- generation were not detected in the pertussis toxin-treated macrophages, suggesting that G proteins are coupled with the C3a receptors of macrophages. Although the C3a-induced O2- generation was inhibited by staurosporine, it was more resistant to staurosporine than phorbol 12-myristate-13-acetate (PMA)-induced O2- generation, suggesting that a protein kinase distinct from protein kinase C may be associated with the C3a receptor.

Expression and cloning of migration inhibitory factor-related protein (MRP)8 and MRP14 in arthritis-susceptible rats.

Rat migration inhibitory factor-related protein 8 (MRP8) and MRP14 were identified during screening of a subtracted cDNA library generated to identify differences in gene expression between LEW/N and F344/N rats. The predicted amino acid sequence of rat MRP8 and MRP14 is 60-80% identical with that from human and mouse. Expression of these genes correlated with chronic inflammation in LEW/N rats, but were absent in F344/N rats which do not develop arthritis in response to streptococcal cell wall peptidoglycan-polysaccharide complexes (SCW). These differences suggest a role for MRP8 and MRP14 in susceptibility to SCW-induced chronic disease.

Cellular responses of guinea-pig macrophages to C4a; inhibition of C3a-induced O2- generation by C4a.

We have investigated the cellular responses of guinea-pig macrophages to human C4a. C4a induced a biphasic Ca2+ mobilization; a rapid temporary Ca2+ mobilization from intracellular Ca2+ pool followed by a weak Ca2+ influx of extracellular Ca2+. Although the C4a-treated macrophages did not respond again to C4a, that is, desensitization to C4a, the C4a-desensitized macrophages still responded to C3a to induce a Ca2+ mobilization. Furthermore, C4a failed to inhibit [125I]-C3a binding to macrophages, suggesting that C4a receptors are different from C3a receptors. In contrast to C3a, C4a-induced Ca2+ mobilization didn't link to O2- generation but inhibited the C3a-induced O2- generation. These results suggest that C4a binds to a specific C4a receptor on guinea-pig macrophages to down-regulate the C3a receptor-mediated O2- generation in macrophages.

Age-related changes in blood concentrations of FSH, LH and testosterone and testicular morphology in a new rat sterile mutant with hereditary aspermia.

A new rat mutant showing aspermia was investigated. Groups of 4-7 mutant male rats were killed at 3, 5, 10, 15 and 25 weeks of age. Examination by microscope showed apparent abnormalities in the seminiferous epithelium from 3 weeks of age onward. Inclusion-like bodies were observed in the cytoplasm of pachytene spermatocytes from 3 weeks old and instead of spermiation, polynuclear giant cells were formed within the seminiferous epithelium after 5 weeks of age. Histological analysis of seminiferous epithelium of adult mutant rats also showed a marked decrease in the number of preleptotene, leptotene and pachytene spermatocytes and tubules containing only spermatogonia and Sertoli cells in the seminiferous epithelium increased with age. However, the combination of other cellular elements of germ cells in the seminiferous epithelium was similar to that in normal rats and the distribution rate of these seminiferous tubules was close to that of normal rats, indicating that cyclicity of seminiferous epithelium was still maintained in the mutant rats despite the lack of spermiation. Plasma concentrations of FSH and LH were significantly higher in the mutant male rats than in normal male rats at 5 and 10 weeks of age onward, respectively. Plasma concentrations of testosterone were lower in the mutant male rats than in normal male rats. Silastic capsules containing testosterone were implanted into the unilateral testis of adult mutant male rats and animals were autopsied 5 weeks later. However, intratesticular administration of testosterone did not affect restoration of spermatogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

[The change with age of the copulatory behavior of the male rats aged 67 and 104 weeks].

Changes with age in sexual fertility in male rats of the Wistar-Imamichi strain were investigated. Litter size and numbers of implantation sites in females mated with males aged 14 to 44 weeks tended to decrease with increased aging of males. These indicators in females mated with males aged over than 44 weeks decreased, compared with that aged 14 to 44 weeks (P < 0.05 to 0.001). In addition, all females mated with males aged 95 weeks were not pregnant. In male copulatory behavior with aging, incidences and numbers of mounting at 67 and 104 weeks of age were 100%, 42.6 +/- 15.3 (Mean +/- S.D.) and 42%, 1.8 +/- 2.8, respectively. The intromission and ejaculation were observed at 67 weeks, but not at 104 weeks of age. These incidences and frequencies were 86%, 10.3 +/- 10.2 for intromission, and 43%, 1.0 +/- 1.3 for ejaculation. Mount latencies (ML) at 67 and 104 weeks of age were 535.4 +/- 607.9 and 3,822.0 +/- 1,753.4 sec, respectively. There were significant differences in ML between two groups (P < 0.05). At 67 weeks of age, intromission and ejaculation latencies, and post-ejaculatory intervals were 2,563.0 +/- 2,216.3, 1,633.7 +/- 977.6, and 657.3 +/- 320.6 sec, respectively. The pregnant rate and numbers of implantation sites in females mated with males aged 67 weeks were 43% and 5.4 +/- 6.8, respectively. In females mated with males aged 104 weeks, all were not pregnant. The weights of tests, epididymides, ventral prostate and seminal vesicles at 104 weeks were light, compared with those at 67 weeks of age (P < 0.05). From these results, the copulatory behavior in male rats of the Wistar-Imamichi strain declined with aging. Sexual fertility in males aged 67 weeks decreased in less than 50%, and males aged 104 weeks showed no intromission and ejaculation.

An aspermia rat mutant (as/as) with spermatogenic failure at meiosis.

A newly identified aspermia rat mutant was investigated on testicular histology and mode of inheritance of the defect. Average testis weight of mutants was about one-third of that of phenotypically normal males. Spermatogenesis was interrupted at meiosis. Pachytene spermatocytes significantly decreased in number. Secondary spermatocytes and few round spermatids were seen, but no elongated spermatids and sperms were observed. A large basophilic inclusion-like body existed in the cytoplasm of late pachytene spermatocytes. Genetic analysis revealed an autosomal recessive transmission of the defect. Aspermia (As) was designated for the locus.

A polymorphism detected in a variable number of tandem repeats (VNTR) of the seminal vesicle secretion (SVS) IV gene in inbred rats.

The second intron of the rat SVS IV gene contains a tandem repeat region of 20-bp sequences. This region was amplified using the polymerase chain reaction to detect variations. Three alleles, characterized by amplified fragments of 750, 490, and 390 bp, respectively, were found in 24 strains examined. This variation segregated in F1 and backcross progeny in an autosomal codominant manner. We tentatively designated this locus Svs-4. Analysis of linkages between the Svs-4 locus and other loci revealed that it was closely linked to the Svp-1 (less than 2.9%) and the a (10.0 +/- 6.7%) loci, which belong to rat linkage group IV. The Svp-1 and Svs-4 loci, however, were differently distributed among the inbred rat strains.