Pivotal role for a tail subunit of the RNA polymerase II mediator complex CgMed2 in azole tolerance and adherence in Candida glabrata.

Antifungal therapy failure can be associated with increased resistance to the employed antifungal agents. Candida glabrata, the second most common cause of invasive candidiasis, is intrinsically less susceptible to the azole class of antifungals and accounts for 15% of all Candida bloodstream infections. Here, we show that C. glabrata MED2 (CgMED2), which codes for a tail subunit of the RNA polymerase II Mediator complex, is required for resistance to azole antifungal drugs in C. glabrata. An inability to transcriptionally activate genes encoding a zinc finger transcriptional factor, CgPdr1, and multidrug efflux pump, CgCdr1, primarily contributes to the elevated susceptibility of the Cgmed2Δ mutant toward azole antifungals. We also report for the first time that the Cgmed2Δ mutant exhibits sensitivity to caspofungin, a constitutively activated protein kinase C-mediated cell wall integrity pathway, and elevated adherence to epithelial cells. The increased adherence of the Cgmed2Δ mutant was attributed to the elevated expression of the EPA1 and EPA7 genes. Further, our data demonstrate that CgMED2 is required for intracellular proliferation in human macrophages and modulates survival in a murine model of disseminated candidiasis. Lastly, we show an essential requirement for CgMed2, along with the Mediator middle subunit CgNut1 and the Mediator cyclin-dependent kinase/cyclin subunit CgSrb8, for the high-level fluconazole resistance conferred by the hyperactive allele of CgPdr1. Together, our findings underscore a pivotal role for CgMed2 in basal tolerance and acquired resistance to azole antifungals.

Fluconazole plus cyclosporine: a fungicidal combination effective against experimental endocarditis due to Candida albicans.

Recent observations demonstrated that fluconazole plus cyclosporine (Cy) synergistically killed Candida albicans in vitro. This combination was tested in rats with C. albicans experimental endocarditis. The MICs of fluconazole and Cy for the test organism were 0.25 and >10 mg/liter, respectively. Rats were treated for 5 days with either Cy, amphotericin B, fluconazole, or fluconazole-Cy. Although used at high doses, the peak concentrations of fluconazole in the serum of rats (up to 4.5 mg/liter) were compatible with high-dose fluconazole therapy in humans. On the other hand, Cy concentrations in serum (up to 4.5 mg/liter) were greater than recommended therapeutic levels. Untreated rats demonstrated massive pseudohyphal growth in both the vegetations and the kidneys. However, only the kidneys displayed concomitant polymorphonuclear infiltration. The therapeutic results reflected this dissociation. In the vegetations, only the fungicidal fluconazole-Cy combination significantly decreased fungal densities compared to all groups, including amphotericin B (P < 0.0001). In the kidneys, all regimens except the Cy regimen were effective, but fluconazole-Cy remained superior to amphotericin B and fluconazole alone in sterilizing the organs (P < 0.0001). While the mechanism responsible for the fluconazole-Cy interaction is hypothetical, this observation opens new perspectives for fungicidal combinations between azoles and other drugs.

NF-kappaB transmits Eda A1/EdaR signalling to activate Shh and cyclin D1 expression, and controls post-initiation hair placode down growth.

A novel function of NF-kappaB in the development of most ectodermal appendages, including two types of murine pelage hair follicles, was detected in a mouse model with suppressed NF-kappaB activity (c(IkappaBalphaDeltaN)). However, the developmental processes regulated by NF-kappaB in hair follicles has remained unknown. Furthermore, the similarity between the phenotypes of c(IkappaBADeltaN) mice and mice deficient in Eda A1 (tabby) or its receptor EdaR (downless) raised the issue of whether in vivo NF-kappaB regulates or is regulated by these novel TNF family members. We now demonstrate that epidermal NF-kappaB activity is first observed in placodes of primary guard hair follicles at day E14.5, and that in vivo NF-kappaB signalling is activated downstream of Eda A1 and EdaR. Importantly, ectopic signals which activate NF-kappaB can also stimulate guard hair placode formation, suggesting a crucial role for NF-kappaB in placode development. In downless and c(IkappaBalphaDeltaN) mice, placodes start to develop, but rapidly abort in the absence of EdaR/NF-kappaB signalling. We show that NF-kappaB activation is essential for induction of Shh and cyclin D1 expression and subsequent placode down growth. However, cyclin D1 induction appears to be indirectly regulated by NF-kappaB, probably via Shh and Wnt. The strongly decreased number of hair follicles observed in c(IkappaBalphaDeltaN) mice compared with tabby mice, indicates that additional signals, such as TROY, must regulate NF-kappaB activity in specific hair follicle subtypes.

A novel Th cell epitope of Candida albicans mediates protection from fungal infection.

Fungal pathogens are a frequent cause of opportunistic infections. They live as commensals in healthy individuals but can cause disease when the immune status of the host is altered. T lymphocytes play a critical role in pathogen control. However, specific Ags determining the activation and function of antifungal T cells remain largely unknown. By using an immunoproteomic approach, we have identified for the first time, to our knowledge, a natural T cell epitope from Candida albicans. Isolation and sequencing of MHC class II-bound ligands from infected dendritic cells revealed a peptide that was recognized by a major population of all Candida-specific Th cells isolated from infected mice. Importantly, human Th cells also responded to stimulation with the peptide in an HLA-dependent manner but without restriction to any particular HLA class II allele. Immunization of mice with the peptide resulted in a population of epitope-specific Th cells that reacted not only with C. albicans but also with other clinically highly relevant species of Candida including the distantly related Candida glabrata. The extent of the reaction to different Candida species correlated with their degree of phylogenetic relationship to C. albicans. Finally, we show that the newly identified peptide acts as an efficient vaccine when used in combination with an adjuvant inducing IL-17A secretion from peptide-specific T cells. Immunized mice were protected from fatal candidiasis. Together, these results uncover a new immune determinant of the host response against Candida ssp. that could be exploited for the development of antifungal vaccines and immunotherapies.

Sténose oesophagienne non-néoplasique: pas toujours si bénigne [Non-neoplastic esophageal stenosis: not always so benign].

Esophageal intramural pseudodiverticulosis is a rare pathology whose etiology is unknown, but which is frequently associated with three highly prevalent entities: esophageal reflux disease, esophageal candidosis and alcoholic esophagitis. With conservative treatment the course of these pathologies is usually benign. However, some severe cases are resistant to conservative treatment and may require more aggressive management. We here present the case of patient suffering from a severe esophagitis complicated by chronic mediastinitis with life-threatening repercussions, requiring esophagectomy as treatment.

Analysis of photoreceptor abnormality in GUCY2D E837D/R838S transgenic pigs

Purpose: We generated genetically engineered pigs expressing the human dominant GUCY2DE837D/R838S allele to modelize cone dystrophy. After a functional follow-up showing reduced photopic ERG responses (ARVO 2011), we analyzed the eyes by immunohistochemistry and revealed retinal modifications in the transgenic group. Methods: Lentiviral vectors encoding the human double mutant GUCY2DE837D/R838S cDNA under the control of a portion of the pig arrestin-3 promoter (Arr3) were produced and used for lentiviral-mediated transgenesis in pigs. Animals were regularly submitted to behavioral and functional investigations and were sacrificed at 4, 7, 15 and 18 months of age for histological and RT-PCR analyses. Retinal markers were used to evaluate the retinal status of eleven transgenic pigs and 6 non-transgenic controls. The expression of the mutant cDNA was also assayed by RT-PCR. Results: A significant increase in the number of displaced nuclei in the outersegment layer is observed in transgenic animals compared to control animals independently of their age. Part of these nuclei originate from cones as demonstrated by colocalization with cone markers. No significant change in the ONL thickness (central and peripheral retina) was measured between 4 and 18 months of age, showing a slow progression of the disease in the transgenic pigs within this time-frame. Conclusions: Arr3-GUCY2DE837D/R838S pigs show signs of retinal abnormality with slow progression which parallels the loss of photopic function. Further characterization of this model should help to elucidate the molecular mechanisms underlying the disease evolution.

Relationship Between the Development of the Spinal Canal and the Etiopathogenesis of Lumbar Spinal Stenosis

INTRODUCTION: The presence of a pre-existing narrow spinal canal may have an important place in the ethiopathogenesis of lumbar spinal stenosis. By consequence the study of the development of the spinal canal is crucial. The first goal of this work is to do a comprehensive literature search and to give an essential view on the development of spinal canal and its depending factors studied until now. The second goal is to give some considerations and hypothesize new leads for clinically useful researches. MATERIALS AND METHODS: A bibliographical research was executed using different search engines: PubMed, Google Schoolar ©, Ovid ® and Web Of Science ©. Free sources and avaible from the University of Lausanne (UNIL) and Centre Hospitalier Universitaire Vaudois (CHUV) were used. At the end of the bibliographic researches 114 references were found, 85 were free access and just 41 were cited in this work. Most of the found references are in English or in French. RESULTS AND DISCUSSION: The spinal canal is principally limited by the vertebrae which have a mesodermal origin. The nervous (ectodermal) tissue significantly influences the growth of the canal. The most important structure participating in the spinal canal growth is the neurocentral synchondrosis in almost the entire vertebral column. The fusion of the half posterior arches seems to have less importance for the canal size. The growth is not homogeneous but, depends on the vertebral level. Timing, rate and growth potentials differ by regions. Especially in the case of the lumbar segment, there is a craniocaudal tendency which entails a greater post-natal catch-up growth for distal vertebrae. Trefoil-shape of the L5 canal is the consequence of a sagittal growth deficiency. The spinal canal shares some developmental characteristics with different structures and systems, especially with the central nervous system. It may be the consequence of the embryological origin. It is supposed that not all the related structures would be affected by a growth impairment because of the different catch-up potentials. Studies found that narrower spinal canals might be related with cardiovascular and gastrointestinal symptoms, lower thymic function, bone mineral content, dental hypoplasia and Harris' lines. Anthropometric correlations found at birth disappear during the pediatric age. All factors which can affect bone and nervous growth might be relevant. Genetic predispositions are the only factors that can never be changed but the real impact is to ascertain. During the antenatal period, all the elements determining a good supply of blood and oxygen may influence the vertebral canal development, for example smoking during pregnancy. Diet is a crucial factor having an impact on both antenatal and postnatal growth. Proteins intake is the only proved dietetic relationship found in the bibliographic research of this work. The mechanical effects due to locomotion changes are unknown. Socioeconomic situation has an impact on several influencing factors and it is difficult to study it owing to numerous bias. CONCLUSIONS: A correct growth of spinal canal is evidently relevant to prevent not-degenerative stenotic conditions. But a "congenital" narrower canal may aggravate degenerative stenosis. This concerns specific groups of patient. If the size of the canal is highly involved in the pathogenesis of common back pains, a hypothetical measure to prevent developmental impairments could have a not- negligible impact on the society. It would be interesting to study more about dietetic necessities for a good spinal canal development. Understanding the relationship between nervous tissues and vertebra it might be useful in identifying what is needed for the ideal development. Genetic importance and the post-natal influences of upright standing on the canal growth remain unsolved questions. All these tracks may have a double purpose: knowing if it is possible to decrease the incidence of narrower spinal canal and consequently finding possible preventive measures. The development of vertebral canal is a complex subject which ranges over a wide variety of fields. The knowledge of this subject is an indispensable tool to understand and hypothesize the influencing factors that might lead to stenotic conditions. Unfortunately, a lack of information makes difficult to have a complete and satisfactory interdisciplinary vision.

ESCMID* guideline for the diagnosis and management of Candida diseases 2012: diagnostic procedures.

As the mortality associated with invasive Candida infections remains high, it is important to make optimal use of available diagnostic tools to initiate antifungal therapy as early as possible and to select the most appropriate antifungal drug. A panel of experts of the European Fungal Infection Study Group (EFISG) of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) undertook a data review and compiled guidelines for the clinical utility and accuracy of different diagnostic tests and procedures for detection of Candida infections. Recommendations about the microbiological investigation and detection of candidaemia, invasive candidiasis, chronic disseminated candidiasis, and oropharyngeal, oesophageal, and vaginal candidiasis were included. In addition, remarks about antifungal susceptibility testing and therapeutic drug monitoring were made.

Candida bloodstream infections in intensive care units: analysis of the extended prevalence of infection in intensive care unit study.

OBJECTIVES: To provide a global, up-to-date picture of the prevalence, treatment, and outcomes of Candida bloodstream infections in intensive care unit patients and compare Candida with bacterial bloodstream infection. DESIGN: A retrospective analysis of the Extended Prevalence of Infection in the ICU Study (EPIC II). Demographic, physiological, infection-related and therapeutic data were collected. Patients were grouped as having Candida, Gram-positive, Gram-negative, and combined Candida/bacterial bloodstream infection. Outcome data were assessed at intensive care unit and hospital discharge. SETTING: EPIC II included 1265 intensive care units in 76 countries. PATIENTS: Patients in participating intensive care units on study day. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Of the 14,414 patients in EPIC II, 99 patients had Candida bloodstream infections for a prevalence of 6.9 per 1000 patients. Sixty-one patients had candidemia alone and 38 patients had combined bloodstream infections. Candida albicans (n = 70) was the predominant species. Primary therapy included monotherapy with fluconazole (n = 39), caspofungin (n = 16), and a polyene-based product (n = 12). Combination therapy was infrequently used (n = 10). Compared with patients with Gram-positive (n = 420) and Gram-negative (n = 264) bloodstream infections, patients with candidemia were more likely to have solid tumors (p < .05) and appeared to have been in an intensive care unit longer (14 days [range, 5-25 days], 8 days [range, 3-20 days], and 10 days [range, 2-23 days], respectively), but this difference was not statistically significant. Severity of illness and organ dysfunction scores were similar between groups. Patients with Candida bloodstream infections, compared with patients with Gram-positive and Gram-negative bloodstream infections, had the greatest crude intensive care unit mortality rates (42.6%, 25.3%, and 29.1%, respectively) and longer intensive care unit lengths of stay (median [interquartile range]) (33 days [18-44], 20 days [9-43], and 21 days [8-46], respectively); however, these differences were not statistically significant. CONCLUSION: Candidemia remains a significant problem in intensive care units patients. In the EPIC II population, Candida albicans was the most common organism and fluconazole remained the predominant antifungal agent used. Candida bloodstream infections are associated with high intensive care unit and hospital mortality rates and resource use.

Microenvironmental reprogramming of thymic epithelial cells to skin multipotent stem cells.

The thymus develops from the third pharyngeal pouch of the anterior gut and provides the necessary environment for thymopoiesis (the process by which thymocytes differentiate into mature T lymphocytes) and the establishment and maintenance of self-tolerance. It contains thymic epithelial cells (TECs) that form a complex three-dimensional network organized in cortical and medullary compartments, the organization of which is notably different from simple or stratified epithelia. TECs have an essential role in the generation of self-tolerant thymocytes through expression of the autoimmune regulator Aire, but the mechanisms involved in the specification and maintenance of TECs remain unclear. Despite the different embryological origins of thymus and skin (endodermal and ectodermal, respectively), some cells of the thymic medulla express stratified-epithelium markers, interpreted as promiscuous gene expression. Here we show that the thymus of the rat contains a population of clonogenic TECs that can be extensively cultured while conserving the capacity to integrate in a thymic epithelial network and to express major histocompatibility complex class II (MHC II) molecules and Aire. These cells can irreversibly adopt the fate of hair follicle multipotent stem cells when exposed to an inductive skin microenvironment; this change in fate is correlated with robust changes in gene expression. Hence, microenvironmental cues are sufficient here to re-direct epithelial cell fate, allowing crossing of primitive germ layer boundaries and an increase in potency.

Gain of function mutations in CgPDR1 of Candida glabrata not only mediate antifungal resistance but also enhance virulence.

CgPdr1p is a Candida glabrata Zn(2)-Cys(6) transcription factor involved in the regulation of the ABC-transporter genes CgCDR1, CgCDR2, and CgSNQ2, which are mediators of azole resistance. Single-point mutations in CgPDR1 are known to increase the expression of at least CgCDR1 and CgCDR2 and thus to contribute to azole resistance of clinical isolates. In this study, we investigated the incidence of CgPDR1 mutations in a large collection of clinical isolates and tested their relevance, not only to azole resistance in vitro and in vivo, but also to virulence. The comparison of CgPDR1 alleles from azole-susceptible and azole-resistant matched isolates enabled the identification of 57 amino acid substitutions, each positioned in distinct CgPDR1 alleles. These substitutions, which could be grouped into three different "hot spots," were gain of function (GOF) mutations since they conferred hyperactivity to CgPdr1p revealed by constitutive high expression of ABC-transporter genes. Interestingly, the major transporters involved in azole resistance (CgCDR1, CgCDR2, and CgSNQ2) were not always coordinately expressed in presence of specific CgPDR1 GOF mutations, thus suggesting that these are rather trans-acting elements (GOF in CgPDR1) than cis-acting elements (promoters) that lead to azole resistance by upregulating specific combinations of ABC-transporter genes. Moreover, C. glabrata isolates complemented with CgPDR1 hyperactive alleles were not only more virulent in mice than those with wild type alleles, but they also gained fitness in the same animal model. The presence of CgPDR1 hyperactive alleles also contributed to fluconazole treatment failure in the mouse model. In conclusion, this study shows for the first time that CgPDR1 mutations are not only responsible for in vitro/in vivo azole resistance but that they can also confer a selective advantage under host conditions.

Early onset collagen VI myopathies: Genetic and clinical correlations.

OBJECTIVE: Mutations in the genes encoding the extracellular matrix protein collagen VI (ColVI) cause a spectrum of disorders with variable inheritance including Ullrich congenital muscular dystrophy, Bethlem myopathy, and intermediate phenotypes. We extensively characterized, at the clinical, cellular, and molecular levels, 49 patients with onset in the first 2 years of life to investigate genotype-phenotype correlations. METHODS: Patients were classified into 3 groups: early-severe (18%), moderate-progressive (53%), and mild (29%). ColVI secretion was analyzed in patient-derived skin fibroblasts. Chain-specific transcript levels were quantified by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), and mutation identification was performed by sequencing of complementary DNA. RESULTS: ColVI secretion was altered in all fibroblast cultures studied. We identified 56 mutations, mostly novel and private. Dominant de novo mutations were detected in 61% of the cases. Importantly, mutations causing premature termination codons (PTCs) or in-frame insertions strikingly destabilized the corresponding transcripts. Homozygous PTC-causing mutations in the triple helix domains led to the most severe phenotypes (ambulation never achieved), whereas dominant de novo in-frame exon skipping and glycine missense mutations were identified in patients of the moderate-progressive group (loss of ambulation). INTERPRETATION: This work emphasizes that the diagnosis of early onset ColVI myopathies is arduous and time-consuming, and demonstrates that quantitative RT-PCR is a helpful tool for the identification of some mutation-bearing genes. Moreover, the clinical classification proposed allowed genotype-phenotype relationships to be explored, and may be useful in the design of future clinical trials.

Typing Candida albicans oral isolates from human immunodeficiency virus-infected patients by multilocus enzyme electrophoresis and DNA fingerprinting.

A total of 189 Candida albicans isolates have been typed by multilocus enzyme electrophoresis. The results obtained confirm the clonal mode of reproduction of C. albicans. The C. albicans populations found in the oropharynx of human immunodeficiency virus (HIV)-infected patients, in the oropharynx of healthy carriers, or in association with invasive candidiasis could not be distinguished. No clone or group of clones could be associated with the appearance of clinical disorders or with a reduced in vitro susceptibility to the antifungal agent fluconazole. Multiple and sequential oral isolates from 24 HIV-infected patients were also typed by restriction enzyme analysis with the enzymes EcoRI and HinfI and by use of the Ca3 repetitive probe. The results obtained by the combination of all three typing methods show that all but one patient each carried a unique major C. albicans clone in their oropharynx. The 21 patients with sequential isolates had the same C. albicans clones in their throats during recurrent oropharyngeal candidiasis episodes, independently of clinical status or of changes of in vitro susceptibility to fluconazole. Finally, several isolates of the same C. albicans clone found simultaneously in the oropharynx of a patient may present different levels of susceptibility to fluconazole.

Urocortins improve dystrophic skeletal muscle structure and function through both PKA- and Epac-dependent pathways.

In Duchenne muscular dystrophy, the absence of dystrophin causes progressive muscle wasting and premature death. Excessive calcium influx is thought to initiate the pathogenic cascade, resulting in muscle cell death. Urocortins (Ucns) have protected muscle in several experimental paradigms. Herein, we demonstrate that daily s.c. injections of either Ucn 1 or Ucn 2 to 3-week-old dystrophic mdx(5Cv) mice for 2 weeks increased skeletal muscle mass and normalized plasma creatine kinase activity. Histological examination showed that Ucns remarkably reduced necrosis in the diaphragm and slow- and fast-twitch muscles. Ucns improved muscle resistance to mechanical stress provoked by repetitive tetanizations. Ucn 2 treatment resulted in faster kinetics of contraction and relaxation and a rightward shift of the force-frequency curve, suggesting improved calcium homeostasis. Ucn 2 decreased calcium influx into freshly isolated dystrophic muscles. Pharmacological manipulation demonstrated that the mechanism involved the corticotropin-releasing factor type 2 receptor, cAMP elevation, and activation of both protein kinase A and the cAMP-binding protein Epac. Moreover, both STIM1, the calcium sensor that initiates the assembly of store-operated channels, and the calcium-independent phospholipase A(2) that activates these channels were reduced in dystrophic muscle by Ucn 2. Altogether, our results demonstrate the high potency of Ucns for improving dystrophic muscle structure and function, suggesting that these peptides may be considered for treatment of Duchenne muscular dystrophy.