Increased IL-1β levels are associated with an imbalance of “oxidant/antioxidant” status during Behçet’s disease

Background

Behçet’s disease is a multisystem disease. It stands at the crossroad between the autoimmunity and auto-inflammatory disorders. In this study, we sought to address a relationship that might exist between interleukin-1β (IL-1β) and the oxidants/antioxidants markers in Behçet’s patients.

Methods

Behçet’s disease patients (n = 78: active stage, n = 28; inactive stage, n = 50) and 41 healthy controls have been included in our study. In this context, we investigated the plasma levels of IL-1β and the nitrosative/oxidative markers: nitric oxide (NO), advanced oxidative protein products (AOPP) and fatty acids peroxidation-malondialdehyde (MDA). The antioxidant system was assessed by measuring the plasma level of superoxide dismutase (SOD) activity. The Mann-Whitney’s U and Pearson’s correlation tests were used for statistical analyses.

Results

Our case-control study showed that patients in active stage displayed higher plasma levels of IL-1β, NO, AOPP and MDA versus healthy controls and patients in inactive stage. Patients in active stage showed significantly lower SOD levels related to patients in inactive stage and healthy controls respectively, whereas patients in inactive stage showed statistically insignificant SOD level versus healthy controls. Correlation studies showed a significant positive correlation between IL-1β and AOPP, IL-1β and NO, and negative correlation between IL-1β and SOD among Behçet’s disease patients. In addition, we showed positive correlation between AOPP and NO, AOPP and MDA and negative correlation between NO and SOD, AOPP and SOD in Behçet’s disease patients.

Conclusion

Interestingly, our study revealed that IL-1β levels increased and correlated with an imbalance of oxidants/antioxidants system, especially during active stage of Behçet disease. Collectively, our study indicates a possible link between IL-1β production and nitrosative/oxidative markers during Behçet’s disease. Exploiting this relationship might provide valuable outputs in the follow-up and prognosis of Behçet’s disease with a potential therapeutic value.

     

Discoidin Domain Receptors: Unique Receptor Tyrosine Kinases in Collagen-mediated Signaling

The discoidin domain receptors (DDRs) are receptor tyrosine kinases that recognize collagens as their ligands. DDRs display unique structural features and distinctive activation kinetics, which set them apart from other members of the kinase superfamily. DDRs regulate cell-collagen interactions in normal and pathological conditions and thus are emerging as major sensors of collagen matrices and potential novel therapeutic targets. New structural and biological information has shed light on the molecular mechanisms that regulate DDR signaling, turnover, and function. This minireview provides an overview of these areas of DDR research with the goal of fostering further investigation of these intriguing and unique receptors.     

Missed Opportunities for Early Access to Care of HIV-Infected Infants in Burkina Faso

Objective

The World Health Organization (WHO) has recommended a universal antiretroviral therapy (ART) for all HIV-infected children before the age of two since 2010, but this implies an early identification of these infants. We described the Prevention of Mother-to-Child HIV Transmission (PMTCT) cascade, the staffing and the quality of infrastructures in pediatric HIV care facilities, in Ouagadougou, Burkina Faso.

Methods

We conducted a cross-sectional survey in 2011 in all health care facilities involved in PMTCT and pediatric HIV care in Ouagadougou. We assessed them according to their coverage in pediatric HIV care and WHO standards, through a desk review of medical registers and a semi-structured questionnaire administered to health-care workers (HCW).

Results

In 2011, there was no offer of care in primary health care facilities for HIV-infected children in Ouagadougou. Six district hospitals and two university hospitals provided pediatric HIV care. Among the 67 592 pregnant women attending antenatal clinics in 2011, 85.9% were tested for HIV. The prevalence of HIV was 1.8% (95% Confidence Interval: 1.7%–1.9%). Among the 1 064 HIV-infected pregnant women attending antenatal clinics, 41.4% received a mother-to-child HIV transmission prevention intervention. Among the HIV-exposed infants, 313 (29.4%) had an early infant HIV test, and 306 (97.8%) of these infants tested received their result within a four-month period. Among the 40 children initially tested HIV-infected, 33 (82.5%) were referred to a health care facility, 3 (9.0%) were false positive, and 27 (90.0%) were initiated on ART. Although health care facilities were adequately supplied with HIV drugs, they were hindered by operational challenges such as shortage of infrastructures, laboratory reagents, and trained HCW.

Conclusions

The PMTCT cascade revealed bottle necks in PMTCT intervention and HIV early infant diagnosis. The staffing in HIV care and quality of health care infrastructures were also insufficient in 2011 in Ouagadougou.     

Association Analysis of IGF2BP2, KCNJ11, and CDKAL1 Polymorphisms with Type 2 Diabetes Mellitus in a Moroccan Population: A Case–Control Study and Meta-analysis

Associations with type 2 diabetes mellitus have been identified for variants CDKAL1 rs7756992, KCNJ11 rs5219, and IGF2BP2 rs4402960 in different populations. In a case–control study of 250 unrelated Moroccan diabetic patients and 250 healthy controls, we used TaqMan allelic discrimination assays to genotype the three SNPs and meta-analysis to investigate the association between the polymorphisms and diabetes in Arab populations. The results showed a significant diabetes association only with the variant rs4402960 of the IGF2BP2 gene under additive 2 (GG vs. TT; p = 0.009) and recessive (TT vs. GG+GT; p = 0.003) models. Meta-analysis indicated significant association between the IGF2BP2 rs4402960 and CDKAL1 rs7756992 polymorphisms and increased risk of diabetes in Arab populations. According to our results, the case–control study and meta-analysis revealed a significant association between the IGF2BP2 rs4402960 variant and type 2 diabetes in Moroccan and Arab populations.     

Secretion of IL-1β triggered by dynasore in murine peritoneal macrophages

The interaction of lipopolysaccharide-primed murine peritoneal macrophages with ivermectin, an antiparasite drug which potentiates P2X(4) receptors and dynasore which inhibits the GTPase activity of dynamin, a protein contributing to the internalization of plasma membrane proteins, was tested. Murine peritoneal macrophages express P2X(4) receptors which are mostly intracellular. In cells from P2X(7)-knockout mice (KO mice), 10 μm adenosine triphosphate (ATP) provoked a transient increase of the intracellular concentration of calcium. Ivermectin had no effect by itself but potentiated the increase of the intracellular concentration of calcium by ATP. The combination of ATP plus ivermectin also decreased the intracellular concentration of potassium and promoted the secretion of IL-1β. Concentrations of dynasore above 50?μm affected the integrity of mitochondria (MTT test) and of the plasma membrane (release of lactate dehydrogenase, LDH). At a 10 μm concentration, dynasore had no effect on the responses to ATP and on the internalization of P2X(4) receptors. By itself dynasore promoted the release of potassium and the secretion of IL-1β after activation of caspase-1. In conclusion, our results confirm that ivermectin potentiates the responses coupled to P2X(4) receptors probably by interaction with an allosteric site. We also show that this potentiation triggers the release of IL-1β by macrophages. As opposed to ivermectin, dynasore has no effect on P2X(4) receptors. This drug triggers a potassium efflux via a mechanism which does not involve purinergic receptors and generates, in consequence, the activation of caspase-1 and the secretion of IL-1β.     

Indole-3-acetic acid is a physiological inhibitor of TORC1 in yeast

Indole-3-acetic acid (IAA) is the most common, naturally occurring phytohormone that regulates cell division, differentiation, and senescence in plants. The capacity to synthesize IAA is also widespread among plant-associated bacterial and fungal species, which may use IAA as an effector molecule to define their relationships with plants or to coordinate their physiological behavior through cell-cell communication. Fungi, including many species that do not entertain a plant-associated life style, are also able to synthesize IAA, but the physiological role of IAA in these fungi has largely remained enigmatic. Interestingly, in this context, growth of the budding yeast Saccharomyces cerevisiae is sensitive to extracellular IAA. Here, we use a combination of various genetic approaches including chemical-genetic profiling, SAturated Transposon Analysis in Yeast (SATAY), and genetic epistasis analyses to identify the mode-of-action by which IAA inhibits growth in yeast. Surprisingly, these analyses pinpointed the target of rapamycin complex 1 (TORC1), a central regulator of eukaryotic cell growth, as the major growth-limiting target of IAA. Our biochemical analyses further demonstrate that IAA inhibits TORC1 both in vivo and in vitro. Intriguingly, we also show that yeast cells are able to synthesize IAA and specifically accumulate IAA upon entry into stationary phase. Our data therefore suggest that IAA contributes to proper entry of yeast cells into a quiescent state by acting as a metabolic inhibitor of TORC1.     

Phlebotomus sergenti in a Cutaneous Leishmaniasis Focus in Azilal Province (High Atlas,Morocco): Molecular Detection and Genotyping of Leishmania tropica,and Feeding Behavior

Background Phlebotomus (Paraphlebotomus) sergenti is at least one of the confirmed vectors for the transmission of cutaneous leishmaniasis caused by Leishmania tropica and distributed widely in Morocco. This form of leishmaniasis is considered largely as anthroponotic, although dogs were found infected with Leishmania tropica, suggestive of zoonosis in some rural areas.ConclusionOur findings supported the notion that Phlebotomus sergenti is the primary vector of Leishmania tropica in this focus, and that the latter is genetically very heterogeneous. Furthermore, our results might be suggestive of a certain level of heterozygosity in Leishmania tropica population. This finding, as well as the feeding of the vectors on different animals are of interest for further investigation.     

Alkalizing drugs induce accumulation of amyloid precursor protein by-products in luminal vesicles of multivesicular bodies

Amyloid precursor protein (APP) metabolism is central to the pathogenesis of Alzheimer disease. We showed recently that the amyloid intracellular domain (AICD), which is released by gamma-secretase cleavage of APP C-terminal fragments (CTFs), is strongly increased in cells treated with alkalizing drugs (Vingtdeux, V., Hamdane, M., Bégard, S., Loyens, A., Delacourte, A., Beauvillain, J.-C., Buée, L., Marambaud, P., and Sergeant, N. (2007) Neurobiol. Dis. 25, 686-696). Herein, we aimed to determine the cell compartment in which AICD accumulates. We show that APP-CTFs and AICD are present in multivesicular structures. Multivesicular bodies contain intraluminal vesicles (known as exosomes) when released in the extracellular space. We demonstrate that APP, APP-CTFs, and AICD are integrated and secreted within exosomes in differentiated neuroblastoma and primary neuronal culture cells. Together with recent data showing that amyloid-beta is also found in exosomes, our data show that multivesicular bodies are essential organelles for APP metabolism and that all APP metabolites can be secreted in the extracellular space.