Identification of the retrotalar pulley of the Flexor Hallucis Longus tendon

Functional Hallux Limitus is the expression of the gliding restraint of the Flexor Hallucis Longus (Fhl) tendon, resulting in several painful syndromes. This impingement is located along the tract of the Fhl tendon at the level of its retrotalar tunnel sealed posteriorly by a fibrous pulley. This pulley, although poorly anatomically characterized, has been arthroscopically proven that its presence or resection plays a pivotal clinical role in the biomechanics of the lower leg, being the main restraint to the physiological movement of the Fhl tendon. The aim of our study was to identify and characterize this anatomical structure. Eleven cadaveric lower legs were initially assessed by computer tomography (CT) imaging, subsequently plastinated, dissected and histologically evaluated by use of Mayer's and Hematoxylin stain. We have shown that the retrotalar pulley of the Fhl shares the same histological characteristics with the retinaculum of the long fibularis muscle and the retinaculum of flexor digitorum muscle, thus it constitutes a different entity than the adjacent formations.

Letter to the editor - round table unites to tackle culture change in an effort to improve animal research reporting

A round table discussion was held during the LAVA-ESLAV-ECLAM conference on Reproducibility of Animal Studies on the 25th of September 2017 in Edinburgh. The aim of the round table was to discuss how to enhance the rate at which the quality of reporting animal research can be improved. This signed statement acknowledges the efforts that participant organizations have made towards improving the reporting of animal studies and confirms an ongoing commitment to drive further improvements, calling upon both academics and laboratory animal veterinarians to help make this cultural change.

Cysteine redox proteomics of the hemoglobin-depleted cytosolic fraction of stored red blood cells

PURPOSE

Erythrocyte concentrates (ECs) represent the most transfused labile blood products. They are stored at 4°C in additive solutions for up to 56 days. Protein oxidation is a marker of oxidative stress and cysteine residues, whose oxidations are required for physiological cell functions, are highly prone to such modification.

EXPERIMENTAL DESIGN

Five ECs from independent donations were followed. Soluble protein extracts were prepared at days 6, 27, and 41, and cysteines were alkylated, reduced, and labeled with infrared dyes. Samples were mixed two by two (day 6 as reference) and analyzed by 2D-DIGE. Detection of labeled cysteines allows quantitative comparison of oxidative status. Spots of interest were analyzed by proteomics.

RESULTS

Thirty-two spots containing 43 proteins were classified as increasing, decreasing, or exhibiting a peak of expression during storage. Proteins having catalytic and antioxidant activities were particularly affected during storage, for example, peroxiredoxin-1 and DJ-1 were reversibly oxidized and catalase was irreversibly oxidized. These proteins could be used to evaluate different storage strategies to maintain proper protein function during the overall storage period.

CONCLUSIONS AND CLINICAL RELEVANCE

This redox-DIGE approach brings new quantitative data on oxidized proteins in stored red blood cells. As previously reported on carbonylation, the oxidative damages differently affect protein functions.

Scientific writing in the laboratory animal sciences

Good communication is important for the dissemination of research results. Here, we summarize the advice that was given to authors at the LA seminar on scientific writing at the FELASA Congress 2016 in Brussels, Belgium on 13–16 June 2016, with the aim of improving the quality of submitted papers and of avoiding common mistakes in scientific reports. See www.felasa2016.eu .

Microtubule Associated Protein 1b (MAP1B) Is a Marker of the Microtubular Cytoskeleton in Podocytes but Is Not Essential for the Function of the Kidney Filtration Barrier in Mice

Podocytes are essential for the function of the kidney glomerular filter. A highly differentiated cytoskeleton is requisite for their integrity. Although much knowledge has been gained on the organization of cortical actin networks in podocyte's foot processes, less is known about the molecular organization of the microtubular cytoskeleton in primary processes and the cell body. To gain an insight into the organization of the microtubular cytoskeleton of the podocyte, we systematically analyzed the expression of microtubule associated proteins (Maps), a family of microtubules interacting proteins with known functions as regulator, scaffold and guidance proteins. We identified microtubule associated protein 1b (MAP1B) to be specifically enriched in podocytes in human and rodent kidney. Using immunogold labeling in electron microscopy, we were able to demonstrate an enrichment of MAP1B in primary processes. A similar association of MAP1B with the microtubule cytoskeleton was detected in cultured podocytes. Subcellular distribution of MAP1B HC and LC1 was analyzed using a double fluorescent reporter MAP1B fusion protein. Subsequently we analyzed mice constitutively depleted of MAP1B. Interestingly, MAP1B KO was not associated with any functional or structural alterations pointing towards a redundancy of MAP proteins in podocytes. In summary, we established MAP1B as a specific marker protein of the podocyte microtubular cytoskeleton.

Plastination and its importance in teaching anatomy. Critical points for long-term preservation of human tissue

Most medical curricula rely on human bodies for teaching macroscopic anatomy. Over the past 20 years, plastination has become an important means of preservation of organs, for well dissected specimens or for body slices. Here, several critical points regarding body donation with legal and ethical considerations for long-term preservation, the use of cadavers in teaching and the preparation of plastinates as an additional teaching tool will be discussed. Silicone S10 is the gold standard in the preparation of plastinates. An important point to respect is the preparation of specimens, since only very well dissected body parts or excellent tissue sections should be plastinated to show the extraordinary aspects of the human anatomy. The preparation of thin and transparent sections and preservation with P40 polyester provides an additional technique to prepare resistant body slices. A selection of samples prepared by S10 and P40 are shown and compared. In addition, Prussian or Berlin blue staining of brain slices is shown to discriminate better between gray and white matter and demonstrate neuroanatomical structures. These plastinates have been used for many years in teaching first- and second-year medical students and have not lost their appeal. Students and staff appreciate the use of such plastinates. One of the advantages is that their use is not restricted to the dissection hall; slices and body parts can be used in any lecture room or in small group teaching. Therefore, ethical and legal questions need to be addressed regarding their specific use. Plastinates do not replace the traditional dissection courses, since students learn best the anatomical features of a given region by hands-on dissection and by exploratory anatomy. Furthermore, plastinates are more rigid and do not allow demonstration of hidden structures; they also become more cumbersome for endoscopy or are too rigid for demonstrating mechanical features of joints. However, although not a replacement for traditional dissections, plastination provides an additional tool for long-term preservation and for teaching human anatomy.

Oxidation and ubiquitination in neurodegeneration

It is widely accepted that protein oxidation is involved in a variety of diseases, including neurodegenerative diseases. Especially during aging, a reduction in anti-oxidant defence mechanisms leads to an increased formation of free radical oxygen species and consequently results in a damage of proteins, including mitochondrial and synaptic ones. Even those proteins involved in repair and protein clearance via the ubiquitin proteasome and lysosomal system are subject to damage and show a reduced function. Here, we will discuss a variety of mechanisms and provide examples where cognition is affected and where repair mechanisms are no longer sufficient to compensate for a dysfunction of damaged proteins or even may become toxic. Next to physiological deficits, an accumulation of deficient proteins in aggresomes may occur and result in a formation of pathological hallmark structures typical for aging and disease. A major challenge is how to prevent aberrant oxidation, given that oxidation plays an essential role in aging and neurodegenerative diseases. Particularly interesting are the possibilities to reduce the formation of radical oxygen species leading to a dysfunction of protein repair and protein clearance, or to a formation of toxic byproducts accelerating neurodegeneration.

Identification of immunogenic proteins of Waddlia chondrophila

Evidence is growing for a role of Waddlia chondrophila as an agent of adverse pregnancy outcomes in both humans and ruminants. This emerging pathogen, member of the order Chlamydiales, is also implicated in bronchiolitis and lower respiratory tract infections. Until now, the serological diagnosis of W. chondrophila infection has mainly relied on manually intensive tests including micro-immunofluorescence and Western blotting. Thus, there is an urgent need to establish reliable high throughput serological assays. Using a combined genomic and proteomic approach, we detected 57 immunogenic proteins of W. chondrophila, of which 17 were analysed by mass spectrometry. Two novel hypothetical proteins, Wim3 and Wim4, were expressed as recombinant proteins in Escherichia coli, purified and used as antigens in an ELISA test. Both proteins were recognized by sera of rabbits immunized with W. chondrophila as well as by human W. chondrophila positive sera but not by rabbit pre-immune sera nor human W. chondrophila negative sera. These results demonstrated that the approach chosen is suitable to identify immunogenic proteins that can be used to develop a serological test. This latter will be a valuable tool to further clarify the pathogenic potential of W. chondrophila.

The role of the ubiquitin proteasome system in Alzheimer's disease

Today, Alzheimer's disease (AD) is one of the most important age-related neurodegenerative diseases, but its etiology remains still unknown. Since the discovery that the hallmark structures of this disease i.e. the formation of amyloid fibers could be the product of ubiquitin-mediated protein degradation defects, it has become clear that the ubiquitin–proteasome system (UPS), usually essential for protein repair, turnover and degradation, is perturbed in this disease. Different aspects of normal and pathological aging are discussed with respect to protein repair and degradation via the UPS, as well as consequences of a deficit in the UPS in AD. Selective protein oxidation may cause protein damage, or protein mutations may induce a dysfunction of the proteasome. Such events eventually lead to activation of cell death pathways and to an aberrant aggregation or incorporation of ubiquitinated proteins into hallmark structures. Aggresome formation is also observed in other neurodegenerative diseases, suggesting that an activation of similar mechanisms must occur in neurodegeneration as a basic phenomenon. It is essential to discuss therapeutic ways to investigate the UPS dysfunction in the human brain and to identify specific targets to hold or stop cell decay.

High throughput sequencing and proteomics to identify immunogenic proteins of a new pathogen: the dirty genome approach

BACKGROUND

With the availability of new generation sequencing technologies, bacterial genome projects have undergone a major boost. Still, chromosome completion needs a costly and time-consuming gap closure, especially when containing highly repetitive elements. However, incomplete genome data may be sufficiently informative to derive the pursued information. For emerging pathogens, i.e. newly identified pathogens, lack of release of genome data during gap closure stage is clearly medically counterproductive.

METHODS/PRINCIPAL FINDINGS

We thus investigated the feasibility of a dirty genome approach, i.e. the release of unfinished genome sequences to develop serological diagnostic tools. We showed that almost the whole genome sequence of the emerging pathogen Parachlamydia acanthamoebae was retrieved even with relatively short reads from Genome Sequencer 20 and Solexa. The bacterial proteome was analyzed to select immunogenic proteins, which were then expressed and used to elaborate the first steps of an ELISA.

CONCLUSIONS/SIGNIFICANCE

This work constitutes the proof of principle for a dirty genome approach, i.e. the use of unfinished genome sequences of pathogenic bacteria, coupled with proteomics to rapidly identify new immunogenic proteins useful to develop in the future specific diagnostic tests such as ELISA, immunohistochemistry and direct antigen detection. Although applied here to an emerging pathogen, this combined dirty genome sequencing/proteomic approach may be used for any pathogen for which better diagnostics are needed. These genome sequences may also be very useful to develop DNA based diagnostic tests. All these diagnostic tools will allow further evaluations of the pathogenic potential of this obligate intracellular bacterium.