Functional characterization of naturally occurring genetic variants in the human TLR1-2-6 gene family

Toll-like receptors (TLRs) are considered an essential component of the innate immune system, initiating inflammatory responses following infection of the host. Humans have 10 functional TLRs, differing in their subcellular distributions and the microbial agonists they sense. The phylogenetically conserved TLR1-2-6 family is unique in that TLR1 and TLR6 form heterodimers with TLR2 to mediate signalling in response to agonists. Epidemiological genetic studies have identified several TLR variants that appear to influence susceptibility to infectious diseases, but the functional consequences of which remain largely unknown. Here, we assessed the functional impact of the TLR1-2-6 variants with altered amino acid sequences segregating naturally in the human population. We used an NF-κB reporter assay in TLR-transfected human embryonic kidney 293T cells stimulated with the corresponding TLR agonists. We found that among the 41 naturally occurring variants with amino acid alterations identified in the TLR1-2-6 family, 14 of them (five TLR1, four TLR2, and five TLR6 variants) displayed marked impairment of NF-κB activation. Most of these variants are present at very low population frequencies and are population-specific. These observations suggest that rare, nonsynonymous TLR mutations are likely to have deleterious effects on immune responses and may therefore contribute to complex susceptibility to infection at the population level.     

Extending the socio-sexual brain: arginine-vasopressin immunoreactive circuits in the telencephalon of mice

Quantitative analysis of the immunoreactivity for arginine-vasopressin (AVP-ir) in the telencephalon of male (intact and castrated) and female CD1 mice allows us to precisely locate two sexually dimorphic (more abundant in intact than castrated males and females) AVP-ir cell groups in the posterior bed nucleus of the stria terminalis (BST) and the amygdala. Chemoarchitecture (NADPH diaphorase) reveals that the intraamygdaloid AVP-ir cells are located in the intra-amygdaloid BST (BSTIA) rather than the medial amygdala (Me), as previously thought. Then, we have used for the first time tract tracing (combined with AVP immunofluorescence) and fiber-sparing lesions of the BST to analyze the projections of the telencephalic AVP-ir cell groups. The results demonstrate that the posterior BST originates the sexually dimorphic innervation of the lateral septum, the posterodorsal Me and a substance P-negative area in the medioventral striato-pallidum (mvStP).The BSTIA may also contribute to some of these terminal fields. Our material also reveals non-dimorphic AVP-ir processes in two locations of the amygdala. First, the ventral Me shows dendrite-like AVP-ir processes apparently belonging supraoptic neurons, whose possible functions are discussed. Second, the Ce shows sparse, thick AVP-ir axons with high individual variability in density and distribution, whose possible influence on stress coping in relation to the affiliative or agonistic behaviors mediated by the Me are discussed. Finally, we propose that the region of the mvStP showing sexually dimorphic AVP-ir innervation is part of the brain network for socio-sexual behavior, in which it would mediate motivational aspects of chemosensory-guided social interactions.     

Avian mycobacteriosis in free-living raptors in Majorca Island,Spain

Avian mycobacteriosis is a chronic, infectious disease caused by different species of mycobacteria, usually belonging to the Mycobacterium avium complex. From 2004 to 2007, 589 raptors brought dead or sick to a wildlife rehabilitation centre in Majorca (Balearic Islands, Spain) were necropsied. The birds belonged to 12 different species, chiefly common kestrel (Falco tinnunculus) (n=297), scops owl (Otus scops) (n=109), barn owl (Tyto alba) (n=75), long-eared owl (Asio otus) (n=58), peregrine falcon (Falco peregrinus) (n=27), and booted eagle (Hieraaetus pennatus) (n=13). Gross lesions compatible with mycobacteriosis were observed in 14 birds (2.4%) found in several locations in Majorca. They were 12 kestrels (prevalence in this species, 4.0%), one long-eared owl (1.7%) and one scops owl (0.9%), all the birds presenting white–yellowish nodules from pinpoint size to 1 cm in diameter in diverse organs, mainly in the liver, spleen and intestine. Affected organs were subjected to bacteriology and molecular identification by polymerase chain reaction and, in all cases, infection with M. avium subspecies avium was confirmed. The observed prevalences are similar to those previously observed in Holland, although the actual prevalence detected in this study is likely to be higher than reported because only birds with gross lesions were subjected to culture. Further molecular characterization with a set of six mycobacterial interspersed repetitive unit–variable number tandem repeat loci was used to sub-type the isolates in order to show the existence of possible epidemiological links. Six different genotypes were found, which points to infection from multiple foci. No temporal or geographical aggregation of the cases was observed to be associated with the presence of positive birds or with the different variable number tandem repeat allelic profiles. The most feasible origin might be water or food sources, although the reservoir of mycobacteria remains unknown.     

FISH mapping of microsatellite loci from <Emphasis Type="Italic">Drosophila subobscura</Emphasis> and its comparison to related species

Microsatellites are highly polymorphic markers that are distributed through all the genome being more abundant in non-coding regions. Whether they are neutral or under selection, these markers if localized can be used as co-dominant molecular markers to explore the dynamics of the evolutionary processes. Their cytological localization can allow identifying genes under selection, inferring recombination from a genomic point of view, or screening for the genomic reorganizations occurring during the evolution of a lineage, among others. In this paper, we report for the first time the localization of microsatellite loci by fluorescent in situ hybridization on Drosophila polytene chromosomes. In Drosophila subobscura, 72 dinucleotide microsatellite loci were localized by fluorescent in situ hybridization yielding unique hybridization signals. In the sex chromosome, microsatellite distribution was not uniform and its density was higher than in autosomes. We identified homologous segments to the sequence flanking the microsatellite loci by browsing the genome sequence of Drosophila pseudoobscura and Drosophila melanogaster. Their localization supports the conservation of Muller’s chromosomal elements among Drosophila species and the existence of multiple intrachromosomal rearrangements within each evolutionary lineage. Finally, the lack of microsatellite repeats in the homologous D. melanogaster sequences suggests convergent evolution for high microsatellite density in the distal part of the X chromosome.     

Determinants of HIV progression and assessment of the optimal time to initiate highly active antiretroviral therapy: PISCIS Cohort (Spain)

OBJECTIVE: We analyze the factors related to progression to AIDS or death in HIV-infected patients from the Proyecto para la Informatización del Seguimiento Clínico epidemiológico de los pacientes con Infección por VIH/SIDA (PISCIS) Cohort and we assess the optimal time to initiate highly active antiretroviral therapy (HAART) taking lead time into account. METHODS: We selected naive patients who were AIDS-free and initiated HAART after January 1998. Statistical analyses were performed using Cox proportional hazards models. Lead time was defined as the time it took the deferred group with an early disease stage to reach the later stage. The analysis accounting for lead time was performed using multiple imputation methods based on estimates from the pre-HAART period as described elsewhere. RESULTS: Multivariate analysis on 2035 patients (median follow-up = 34.3 months) showed significantly higher hazard ratios (HRs) for a CD4 count <200 cells/microL (HR = 3.79, 95% confidence interval [CI]: 2.18 to 6.57), HIV-1 RNA level >100,000 copies/mL (HR = 1.84, 95% CI: 1.26 to 2.69), and hepatitis C virus (HCV) coinfection (HR = 2.40, 95% CI: 1.65 to 3.49), whereas a lower risk was found for those who started HAART between January 2001 and June 2004 (HR = 0.55, 95% CI: 0.30 to 0.90). When lead time and unseen events were included, we found a higher risk of progression to AIDS among patients who deferred treatment when the CD4 count reached <200 cells/microL (HR = 2.97, 95% CI: 1.91 to 4.63) and 200 to 350 cells/microL (HR = 1.85, 95% CI: 1.03 to 3.33) compared with those who started treatment with CD4 counts from 200 to 350 cells/microL and >350 cells/microL, respectively. CONCLUSIONS: Advanced HIV disease, HCV coinfection, and early HAART period were determinants of AIDS progression or death. Lead-time analysis in asymptomatic HIV-infected patients suggests that the best time to start HAART is before the CD4 count falls to lower than 350 cells/microL.     

Successful conversion from twice-daily to once-daily tacrolimus in liver transplantation: observational multicenter study

Dopazo C, Rodriguez R, Llado L, Calatayud D, Castells L, Ramos E, Molina V, García R, Fabregat J, Charco R. Successful conversion from twice‐daily to once‐daily tacrolimus in liver transplantation: observational multicenter study.
Clin Transplant 2012: 26: E32–E37.
© 2011 John Wiley & Sons A/S. Background: Compliance with immunosuppressive therapy in liver transplant patients is critical to prevent acute organ rejection and/or late graft loss. Strategies to simplify the therapeutic regimen may improve adherence. Aim: To evaluate the safety and efficacy of conversion from a twice‐daily to once‐daily tacrolimus formulation in adult liver transplant patients. Patients and methods: This prospective observational multicenter study included 187 liver transplant patients with at least 10 months post‐transplant follow‐up, no rejection episodes in the last three months, and creatinine levels <2 mg/dL. Conversion from a twice‐daily to a once‐daily formulation was based on a 1:1 proportion. Results: Median age was 61 yr (range: 28–80 yr); 64% were men and 36% women. The main indications for liver transplant were alcoholic cirrhosis in 30%. Median conversion time was 55 months (range: 10–215 months). Serum tacrolimus levels decreased at one month after conversion (pre‐conversion levels = 5.4 ± 3.0 ng/mL vs. post‐conversion levels = 4.4 ± 2.4 ng/mL, p = 0.013); however, these values normalized at six months post‐conversion with no changes in liver function and rejection episodes were observed only in two patients. Conclusion: Conversion from a twice‐daily to a once‐daily tacrolimus formulation is a safe, effective strategy in the management of stable liver transplant patients.     

Cell-Autonomous Inactivation of the Reelin Pathway Impairs Adult Neurogenesis in the Hippocampus

Adult hippocampal neurogenesis is thought to be essential for learning and memory, and has been implicated in the pathogenesis of several disorders. Although recent studies have identified key factors regulating neuroprogenitor proliferation in the adult hippocampus, the mechanisms that control the migration and integration of adult-born neurons into circuits are largely unknown. Reelin is an extracellular matrix protein that is vital for neuronal development. Activation of the Reelin cascade leads to phosphorylation of Disabled-1, an adaptor protein required for Reelin signaling. Here we used transgenic mouse and retroviral reporters along with Reelin signaling gain-of-function and loss-of-function studies to show that the Reelin pathway regulates migration and dendritic development of adult-generated hippocampal neurons. Whereas overexpression of Reelin accelerated dendritic maturation, inactivation of the Reelin signaling pathway specifically in adult neuroprogenitor cells resulted in aberrant migration, decreased dendrite development, formation of ectopic dendrites in the hilus, and the establishment of aberrant circuits. Our findings support a cell-autonomous and critical role for the Reelin pathway in regulating dendritic development and the integration of adult-generated granule cells and point to this pathway as a key regulator of adult neurogenesis. Moreover, our data reveal a novel role of the Reelin cascade in adult brain function with potential implications for the pathogenesis of several neurological and psychiatric disorders.     

Enfermedad pulmonar intersticial difusa por metaplasia peribronquiolar

Peribronchiolar metaplasia is a histologic lesion characterized by fibrosis and bronchiolar epithelial proliferation, affecting peribronchiolar alveolar septa and terminal bronchioles. It has been considered a nonspecific tissue reaction secondary to the action of external factors, such as tobacco smoke and microbes, and is a common histologic finding in several diffuse interstitial lung diseases. Several such cases with clinical, radiologic, and lung function manifestations characteristic of idiopathic interstitial pneumonia have been described recently, all having peribronchiolar metaplasia as the only histologic abnormality. We report 2 cases of interstitial lung disease in which peribronchiolar metaplasia was the only finding of pathology.