Hedgehog signaling governs the development of otic sensory epithelium and its associated innervation in zebrafish

The inner ear is responsible for the perception of motion and sound in vertebrates. Its functional unit, the sensory patch, contains mechanosensory hair cells innervated by sensory neurons from the statoacoustic ganglion (SAG) that project to the corresponding nuclei in the brainstem. How hair cells develop at specific positions, and how otic neurons are sorted to specifically innervate each endorgan and to convey the extracted information to the hindbrain is not completely understood. In this work, we study the generation of macular sensory patches and investigate the role of Hedgehog (Hh) signaling in the production of their neurosensory elements. Using zebrafish transgenic lines to visualize the dynamics of hair cell and neuron production, we show that the development of the anterior and posterior maculae is asynchronic, suggesting they are independently regulated. Tracing experiments demonstrate the SAG is topologically organized in two different neuronal subpopulations, which are spatially segregated and innervate specifically each macula. Functional experiments identify the Hh pathway as crucial in coordinating the production of hair cells in the posterior macula, and the formation of its specific innervation. Finally, gene expression analyses suggest that Hh influences the balance between different SAG neuronal subpopulations. These results lead to a model in which Hh orients functionally the development of inner ear towards an auditory fate in all vertebrate species.

Genetic variation in LIN28B is associated with the timing of puberty.

The timing of puberty is highly variable. We carried out a genome-wide association study for age at menarche in 4,714 women and report an association in LIN28B on chromosome 6 (rs314276, minor allele frequency (MAF) = 0.33, P = 1.5 x 10(-8)). In independent replication studies in 16,373 women, each major allele was associated with 0.12 years earlier menarche (95% CI = 0.08-0.16; P = 2.8 x 10(-10); combined P = 3.6 x 10(-16)). This allele was also associated with earlier breast development in girls (P = 0.001; N = 4,271); earlier voice breaking (P = 0.006, N = 1,026) and more advanced pubic hair development in boys (P = 0.01; N = 4,588); a faster tempo of height growth in girls (P = 0.00008; N = 4,271) and boys (P = 0.03; N = 4,588); and shorter adult height in women (P = 3.6 x 10(-7); N = 17,274) and men (P = 0.006; N = 9,840) in keeping with earlier growth cessation. These studies identify variation in LIN28B, a potent and specific regulator of microRNA processing, as the first genetic determinant regulating the timing of human pubertal growth and development.

In vitro effect of malachite green on Candida albicans involves multiple pathways and transcriptional regulators UPC2 and STP2.

In this study, we show that a chemical dye, malachite green (MG), which is commonly used in the fish industry as an antifungal, antiparasitic, and antibacterial agent, could effectively kill Candida albicans and non-C. albicans species. We have demonstrated that Candida cells are susceptible to MG at a very low concentration (MIC that reduces growth by 50% [MIC(50)], 100 ng ml(-1)) and that the effect of MG is independent of known antifungal targets, such as ergosterol metabolism and major drug efflux pump proteins. Transcriptional profiling in response to MG treatment of C. albicans cells revealed that of a total of 207 responsive genes, 167 genes involved in oxidative stress, virulence, carbohydrate metabolism, heat shock, amino acid metabolism, etc., were upregulated, while 37 genes involved in iron acquisition, filamentous growth, mitochondrial respiration, etc., were downregulated. We confirmed experimentally that Candida cells exposed to MG resort to a fermentative mode of metabolism, perhaps due to defective respiration. In addition, we showed that MG triggers depletion of intracellular iron pools and enhances reactive oxygen species (ROS) levels. These effects could be reversed by the addition of iron or antioxidants, respectively. We provided evidence that the antifungal effect of MG is exerted through the transcription regulators UPC2 (regulating ergosterol biosynthesis and azole resistance) and STP2 (regulating amino acid permease genes). Taken together, our transcriptome, genetic, and biochemical results allowed us to decipher the multiple mechanisms by which MG exerts its anti-Candida effects, leading to a metabolic shift toward fermentation, increased generation of ROS, labile iron deprivation, and cell necrosis.

Coat color dilution in mice because of inactivation of the melanoma antigen MART-1.

Melanoma antigen recognized by T cells 1 (MART-1) is a melanoma-specific antigen, which has been thoroughly studied in the context of immunotherapy against malignant melanoma and which is found only in the pigment cell lineage. However, its exact function and involvement in pigmentation is not clearly understood. Melanoma antigen recognized by T cells 1 has been shown to interact with the melanosomal proteins Pmel17 and OA1. To understand the function of MART-1 in pigmentation, we developed a new knockout mouse model. Mice deficient in MART-1 are viable, but loss of MART-1 leads to a coat color phenotype, with a reduction in total melanin content of the skin and hair. Lack of MART-1 did not affect localization of melanocyte-specific proteins nor maturation of Pmel17. Melanosomes of hair follicle melanocytes in MART-1 knockout mice displayed morphological abnormalities, which were exclusive to stage III and IV melanosomes. In conclusion, our results suggest that MART-1 is a pigmentation gene that is required for melanosome biogenesis and/or maintenance.

Besondere Haarstrukturen der Soricidae (Mammalia, Insectivora) und ihre taxonomische Deutung

The following study should clear up the structures of the H-shaped profile found in the hairs of some shrews and show if it has a taxonomic signification. Therefore we studied the concerned hair structures by scanning electron microscopy in 8 genera. The special hair-shape, which is confined to the terminal segment of guard hairs, is found in the species of the following genera:Sorex, Neomys, Blarina andCryptotis, all members of the subfamily Soricinae. All the examined members of the subfamily Crocidurinae, i.e.Crocidura, Praesorex, Suncus andSylvisorex show a simple hair shape. The H-shaped hair characterizes the Soricinae as a monophyletic unity. Yet, the morphological criteria of hair complete the osteological criteria of Repenning (1967) an plead for the validitiy of the often refuted subfamilies.

Generation and characterization of function-blocking anti-ectodysplasin A (EDA) monoclonal antibodies that induce ectodermal dysplasia.

Development of ectodermal appendages, such as hair, teeth, sweat glands, sebaceous glands, and mammary glands, requires the action of the TNF family ligand ectodysplasin A (EDA). Mutations of the X-linked EDA gene cause reduction or absence of many ectodermal appendages and have been identified as a cause of ectodermal dysplasia in humans, mice, dogs, and cattle. We have generated blocking antibodies, raised in Eda-deficient mice, against the conserved, receptor-binding domain of EDA. These antibodies recognize epitopes overlapping the receptor-binding site and prevent EDA from binding and activating EDAR at close to stoichiometric ratios in in vitro binding and activity assays. The antibodies block EDA1 and EDA2 of both mammalian and avian origin and, in vivo, suppress the ability of recombinant Fc-EDA1 to rescue ectodermal dysplasia in Eda-deficient Tabby mice. Moreover, administration of EDA blocking antibodies to pregnant wild type mice induced in developing wild type fetuses a marked and permanent ectodermal dysplasia. These function-blocking anti-EDA antibodies with wide cross-species reactivity will enable study of the developmental and postdevelopmental roles of EDA in a variety of organisms and open the route to therapeutic intervention in conditions in which EDA may be implicated.

Indicator displacement assays as molecular timers

Dynamic mixtures of Rh-dye complexes can be used to determine the history of chemical events such as the addition of ATP and ADP by UV-vis spectroscopy.

Androgenetic alopecia: identification of four genetic risk loci and evidence for the contribution of WNT signaling to its etiology.

The pathogenesis of androgenetic alopecia (AGA, male-pattern baldness) is driven by androgens, and genetic predisposition is the major prerequisite. Candidate gene and genome-wide association studies have reported that single-nucleotide polymorphisms (SNPs) at eight different genomic loci are associated with AGA development. However, a significant fraction of the overall heritable risk still awaits identification. Furthermore, the understanding of the pathophysiology of AGA is incomplete, and each newly associated locus may provide novel insights into contributing biological pathways. The aim of this study was to identify unknown AGA risk loci by replicating SNPs at the 12 genomic loci that showed suggestive association (5 × 10(-8)<P<10(-5)) with AGA in a recent meta-analysis. We analyzed a replication set comprising 2,759 cases and 2,661 controls of European descent to confirm the association with AGA at these loci. Combined analysis of the replication and the meta-analysis data identified four genome-wide significant risk loci for AGA on chromosomes 2q35, 3q25.1, 5q33.3, and 12p12.1. The strongest association signal was obtained for rs7349332 (P=3.55 × 10(-15)) on chr2q35, which is located intronically in WNT10A. Expression studies in human hair follicle tissue suggest that WNT10A has a functional role in AGA etiology. Thus, our study provides genetic evidence supporting an involvement of WNT signaling in AGA development.

Trends in prevalence, awareness, treatment and control of hypertension in the Republic of Seychelles (African region) between 1989 and 2013

Objective: We assessed the awareness, treatment and control of hypertension in the Seychelles between 1989 and 2013. In the Seychelles, heath care is free to all inhabitants within a national health system, inclusive all hypertension medications. Design and method: Four surveys were conducted in 1989, 1994, 2004 and 2013 (Seychelles Heart Studies I, II, III and IV) in random samples of the population aged 25-64 (N >1000 and participation rate >75% in each sur acceptance of the program, though no objective index could be calculated. In total, 15% of device measurements were above high normal values and would correspond to either newly diagnosed HNT (second measurement required) or to poorly controlled known HTN. It should be stressed that 53 women without HTN who completed the questionnaire had abnormal BP values, including the 29 women who also contacted the research team. It could be speculated that approximately 2% of women would be first diagnosed with HTN following the completion of the initial phase of the screening program. Conclusions: Hypertension screening in the hair salon setting was proved to be conveniently applicable and well accepted both by owners and by customers and could lead to the new diagnosis of hypertension for 2% of the female clients. Further research is warranted to assess the effectiveness of the program.

Secreted proteases from dermatophytes

Dermatophytes are highly specialized pathogenic fungi that exclusively infect the stratum corneum, nails or hair, and it is evident that secreted proteolytic activity is important for their virulence. Endo- and exoproteases-secreted by dermatophytes are similar to those of species of the genus Aspergillus. However, in contrast to Aspergillus spp., dermatophyte-secreted endoproteases are multiple and are members of two large protein families, the subtilisins (serine proteases) and the fungalysins (metalloproteases). In addition, dermatophytes excrete sulphite as a reducing agent. In the presence of sulphite, disulphide bounds of the keratin substrate are directly cleaved to cysteine and S-sulphocysteine, and reduced proteins become accessible for further digestion by various endo- and exoproteases secreted by the fungi. Sulphitolysis is likely to be an essential step in the digestion of compact keratinized tissues which precedes the action of all proteases.

Imaging pheromone sensing in a mouse vomeronasal acute tissue slice preparation.

Peter Karlson and Martin Lüscher used the term pheromone for the first time in 1959 to describe chemicals used for intra-species communication. Pheromones are volatile or non-volatile short-lived molecules secreted and/or contained in biological fluids, such as urine, a liquid known to be a main source of pheromones. Pheromonal communication is implicated in a variety of key animal modalities such as kin interactions, hierarchical organisations and sexual interactions and are consequently directly correlated with the survival of a given species. In mice, the ability to detect pheromones is principally mediated by the vomeronasal organ (VNO), a paired structure located at the base of the nasal cavity, and enclosed in a cartilaginous capsule. Each VNO has a tubular shape with a lumen allowing the contact with the external chemical world. The sensory neuroepithelium is principally composed of vomeronasal bipolar sensory neurons (VSNs). Each VSN extends a single dendrite to the lumen ending in a large dendritic knob bearing up to 100 microvilli implicated in chemical detection. Numerous subpopulations of VSNs are present. They are differentiated by the chemoreceptor they express and thus possibly by the ligand(s) they recognize. Two main vomeronasal receptor families, V1Rs and V2Rs, are composed respectively by 240 and 120 members and are expressed in separate layers of the neuroepithelium. Olfactory receptors (ORs) and formyl peptide receptors (FPRs) are also expressed in VSNs. Whether or not these neuronal subpopulations use the same downstream signalling pathway for sensing pheromones is unknown. Despite a major role played by a calcium-permeable channel (TRPC2) present in the microvilli of mature neurons TRPC2 independent transduction channels have been suggested. Due to the high number of neuronal subpopulations and the peculiar morphology of the organ, pharmacological and physiological investigations of the signalling elements present in the VNO are complex. Here, we present an acute tissue slice preparation of the mouse VNO for performing calcium imaging investigations. This physiological approach allows observations, in the natural environment of a living tissue, of general or individual subpopulations of VSNs previously loaded with Fura-2AM, a calcium dye. This method is also convenient for studying any GFP-tagged pheromone receptor and is adaptable for the use of other fluorescent calcium probes. As an example, we use here a VG mouse line, in which the translation of the pheromone V1rb2 receptor is linked to the expression of GFP by a polycistronic strategy.

Evaluation of adherence to measures for the prevention of surgical site infections by the surgical team

AbstractOBJECTIVEEvaluate pre- and intraoperative practices adopted by medical and nursing teams for the prevention of surgical infections.METHODA prospective study carried out in the period of April to May 2013, in a surgical center of a university hospital in Belo Horizonte, Minas Gerais.RESULTS18 surgeries were followed and 214 surgical gloves were analyzed, of which 23 (10.7%) had postoperative glove perforation detected, with 52.2% being perceived by users. Hair removal was performed on 27.7% of patients in the operating room, with the use of blades in 80% of the cases. Antibiotic prophylaxis was administered to 81.8% of patients up to 60 minutes prior to surgical incision. An average of nine professionals were present during surgery and the surgery room door remained open in 94.4% of the procedures.CONCLUSIONPartial adhesion to the recommended measures was identified, reaffirming a need for greater attention to these critical steps/actions in order to prevent surgical site infection.

Índices predictivos de fibrosis en la detección del hígado graso no alcohólico: utilidad en Atención Primaria.

El hígado graso no alcohólico(HGNA) es una entidad muy prevalente que se asocia con un aumento del riesgo cardiovascular global. Normalmente es asintomática. Los índices serológicos de fibrosis se están investigando para su diagnóstico. Objetivo: analizar la utilidad de los índices HAIR, FLI y LAP para el diagnóstico del HGNA y la concordancia entre ellos. Metodología: estudio descriptivo, poblacional, multicéntrico realizado en Atención Primaria en sujetos sanos de entre 15-85 años. Las prevalencias fueron de HAIR 68,1%, FLI 46,8%, LAP 56%. Concordancia modesta de los índices. Es necesario seguir investigando para encontrar un índice útil para el diagnóstico.

Lineage potential, plasticity and environmental reprogramming of epithelial stem/progenitor cells.

Recent evidence supports and reinforces the concept that environmental cues may reprogramme somatic cells and change their natural fate. In the present review, we concentrate on environmental reprogramming and fate potency of different epithelial cells. These include stratified epithelia, such as the epidermis, hair follicle, cornea and oesophagus, as well as the thymic epithelium, which stands alone among simple and stratified epithelia, and has been shown recently to contain stem cells. In addition, we briefly discuss the pancreas as an example of plasticity of intrinsic progenitors and even differentiated cells. Of relevance, examples of plasticity and fate change characterize pathologies such as oesophageal metaplasia, whose possible cell origin is still debated, but has important implications as a pre-neoplastic event. Although much work remains to be done in order to unravel the full potential and plasticity of epithelial cells, exploitation of this phenomenon has already entered the clinical arena, and might provide new avenues for future cell therapy of these tissues.

The role of LEKTI in fate determination of keratinocyte stem cells

SPINK5 (serine protease inhibitor Kazal-type 5) encodes the putative proteinase inhibitor LEKTI (lympho-epithelial Kazal-type related inhibitor). In skin, LEKTI expression is restricted to the stratum granulosum of the epidermis and the inner root sheath of hair follicles. Mutations that create premature termination codons in SPINK5 have been reported as the cause of Netherton syndrome (NS), a human autosomal recessive disorder characterized by congenital ichthyosis with defective cornification, a specific hair shaft defect known as trichorrexis invaginata or 'bamboo hair', and severe atopic manifestations, including atopic dermatitis and hayfever. Althought recombinant human LEKTI inhibits a battery of serine proteases including plasmin, trypsin, subtilisin A, cathepsin G, and elastase, the precise role of LEKTI in the physiopathology of NS remains unclear. Spink5−/− mice display a NS-like phenotype. Surprisingly, a psoriasis-like hyperplasia, basement membrane breakdown followed by evagination of spindle-shaped epidermal cells into the dermal compartment, and the presence of numerous sweat gland-like structures were also observed when the skin of Spink5−/− newborn mice, which die at birth, was transplanted onto the back of nude mice. Collectively, these observations suggest that LEKTI may play a role on cell proliferation and stem cell fate. Our current work aims at elucidating the mechanisms by which LEKTI impact these biological processes. Using keratinocyte stem cells obtained from NS patients, we have identified LEKTI as a regulator node in several signaling pathways involved in stem cell behavior.