Prevalence of transmitted nucleoside analogue-resistant HIV-1 strains and pre-existing mutations in pol reverse transcriptase and protease region : outcome after treatment in recently infected individuals

We retrospectively studied 38 Italian recently HIV-1-infected subjects who seroconverted from 1994 to 1997 to investigate: (i) the prevalence of nucleoside reverse transcriptase inhibitors (NRTI)-related mutations at primary infection; (ii) the proportion of naturally occurring mutations in reverse transcriptase (RT) and protease regions of patients naive for non-nucleoside RT inhibitors (NNRTIs) and protease inhibitors (PIs); (iii) the drug-susceptibility to NRTIs and PIs in subjects with NRTI- and/or PI-related mutations; and (iv) the outcome of seroconverters treated with various NRTIs or NRTI/PI regimens. Baseline HIV-1 plasma viraemia and absolute CD4 count at baseline could not be used to distinguish patients with NRTI- and/or PI-related pre-existing mutations from those with wild-type virus (P = 0.693 and P = 0.542, respectively). The frequency of zidovudine-related mutations was 21% in the study period. The response to treatment was not significantly different in subjects with or without genotypic zidovudine-related mutations at primary infection (P = 0.744 for HIV-1 RNA and P = 0.102 for CD4 cells). Some natural variation (2.6%) was present within regions 98-108 and 179-190 of RT involved in NNRTI resistance. The high natural polymorphism in the protease region present in our patients was similar to that reported by others. In our study some PI-associated substitutions, thought to be compensatory in protease enzymatic function, could confer intermediate to high PI-resistance. As discrepancies between genotypic and phenotypic results may exist in recent seroconverters, our data suggest that the role of transmitted NRTI- and PI-resistant variants remain to be fully elucidated in vivo

Identification of two distinct subsets of long-term nonprogressors with divergent viral activity by stromal-derived factor 1 chemokine gene polymorphism analysis

Stromal-derived factor (SDF)-1, the natural ligand for CXCR4, is present in a common polymorphic variant defined by a G-->A transition in the 3' untranslated region of the gene. In persons infected with human immunodeficiency virus type 1 (HIV-1), the homozygous genotype (SDF1-3'A/3'A) has been postulated to interfere with the appearance of T-tropic syncytium-inducing strains. The polymorphism of SDF1 was correlated with HIV-1 phenotype, plasma viremia, and unspliced and multiply spliced specific transcripts in 158 virologically characterized HIV-1-infected patients (39 recent seroconverters, 75 typical progressors, and 44 AIDS patients) and in 42 HIV-1-infected long-term nonprogressors (LTNPs). Analysis of SDF1 allele distribution revealed that SDF1-3'A/3'A status is associated with low CD4 cell count (P=.0449) but not with a specific HIV-1 phenotype. In LTNPs, SDF1-+/+ condition defined a subset of persons with lower HIV-1 replication than in heterozygous subjects. The low viral activity in SDF1-+/+ LTNPs suggests that other factors play a major role in vivo in determining the course of HIV-1 infection

The Role of Muscle microRNAs in Repairing the Neuromuscular Junction

microRNAs have been implicated in mediating key aspects of skeletal muscle development and responses to diseases and injury. Recently, we demonstrated that a synaptically enriched microRNA, miR-206, functions to promote maintenance and repair of the neuromuscular junction (NMJ); in mutant mice lacking miR-206, reinnervation is impaired following nerve injury and loss of NMJs is accelerated in a mouse model of amyotrophic lateral sclerosis (ALS). Here, we asked whether other microRNAs play similar roles. One attractive candidate is miR-133b because it is in the same transcript that encodes miR-206. Like miR-206, miR-133b is concentrated near NMJs and induced after denervation. In miR-133b null mice, however, NMJ development is unaltered, reinnervation proceeds normally following nerve injury, and disease progression is unaffected in the SOD1(G93A) mouse model of ALS. To determine if miR-206 compensates for the loss of miR-133b, we generated mice lacking both microRNAs. The phenotype of these double mutants resembled that of miR-206 single mutants. Finally, we used conditional mutants of Dicer, an enzyme required for the maturation of most microRNAs, to generate mice in which microRNAs were depleted from skeletal muscle fibers postnatally, thus circumventing a requirement for microRNAs in embryonic muscle development. Reinnervation of muscle fibers following injury was impaired in these mice, but the defect was similar in magnitude to that observed in miR-206 mutants. Together, these results suggest that miR-206 is the major microRNA that regulates repair of the NMJ following nerve injury.National Institutes of Health (U.S.) (NIH grant R01AG032322)National Institute of Neurological Disorders and Stroke (U.S.) (NRSA Postdoctoral Fellowship from NINDS/NIH)Ruth K. Broad Biomedical Research Foundation (Fellowship)McGovern Institute for Brain Research at MIT (Poitras Center for Affective Disorders Research

The role of preferential interactions between similar domains in determining the behavior of aqueous solutions of aminoalkanols. A microcalorimetric study

Enthalpies of dilution of binary aqueous solutions containing 1 mol kg-1 NaOH as cosolvent and the homologous series of α,ω-aminoalkanols and 2-amino-1-alkanols as solutes have been determined by flow microcalorimetry at 298 K. Enthalpic self and cross interaction coefficients of the virial expansion of the excess enthalpies were evaluated. These coefficients are positive and increase at increasing alkyl chain length. The difference between the coefficients of positional isomers of aminoalkanols resembles that shown by the corresponding diols in water. The cross interaction coefficient relative to the ternary system containing hexane-1,6-diamine and hexane-1,6-diol is smaller than those relative to the respective binary solutions. The coefficients were interpreted using the "preferential configuration" model: it is inferred that interactions between like hydrophilic groups are preferred when compared to the like-unlike ones

Role of CCR5, CCR2 and SDF-1 gene polymorphisms in a population of HIV-1 infected individuals

The finding that in addition to CD4 molecule HIV-1 uses, CCR5 or CXCR4 receptors to enter target cells prompted the research to identify polymorphisms in coreceptor genes affecting disease progression. In this study we analyzed the prevalence of CCR5-delta32, CCR2-641 and SDF1-3'A alleles in a highly selected group of 42 Long-Term Nonprogressors (LTNPs) compared to 112 subjects with a typical course of HIV-1 infection (TPs) and 117 healthy controls (HCs). In addition, we correlated CCR5, CCR2 and SDF-1 genotypes with molecular indexes of HIV-1 replication, cell-free RNA and both unspliced (US) and multiply spliced (MS) intracellular transcripts, to investigate the role of the mutant alleles in determining a long-term nonprogressive course of HIV-1 disease. Our results indicate a significantly higher prevalence of CCR5-delta32 allele in LTNPs compared to TPs (p=0.0434), while the proportions of CCR2-64I and SDF1-3'A alleles were comparable between the two groups. However, SDF-1 wild type LTNP subjects showed significantly lower levels of HIV-1 genomic RNA, US and MS transcripts than SDF1-3'A heterozygous ones (p=0.0021, 0.016, 0.0031, respectively), whereas both CCR5 and CCR2 wild type individuals had similar rates of viral replication compared to CCR5-delta32 and CCR2-64I heterozygous ones. CCR5, CCR2 and SDF-1 combined genotypes were also studied and this analysis did not identify a specific protective cluster of alleles in LTNPs. Taken together, our results indicate that genetic background involving CCR5, CCR2 and SDF-1 alleles may play a limited role in the natural history of HIV-1 infection