The sulfate-binding site structure of the human eosinophil cationic protein as revealed by a new crystal form

The human eosinophil cationic protein (ECP), also known as RNase 3, is an eosinophil secretion protein that is involved in innate immunity and displays antipathogen and proinflammatory activities. ECP has a high binding affinity for heterosaccharides, such as bacterial lipopolysaccharides and heparan sulfate found in the glycocalix of eukaryotic cells. We have crystallized ECP in complex with sulfate anions in a new monoclinic crystal form. In this form, the active site groove is exposed, providing an alternative model for ligand binding studies. By exploring the protein-sulfate complex, we have defined the sulfate binding site architecture. Three main sites (S1-S3) are located in the protein active site; S1 and S2 overlap with the phosphate binding sites involved in RNase nucleotide recognition. A new site (S3) that is unique to ECP is one of the key anchoring points for sulfated ligands. Arg 1 and Arg 7 in S3, together with Arg 34 and Arg 36 in S1, form the main basic clusters that assist in the recognition of ligand anionic groups. The location of additional sulfate bound molecules, some of which contribute to the crystal packing, may mimic the binding to extended anionic polymers. In conclusion, the structural data define a binding pattern for the recognition of sulfated molecules that can modulate the role of ECP in innate immunity. The results reveal the structural basis for the high affinity of ECP for glycosaminoglycans and can assist in structure-based drug design of inhibitors of the protein cytotoxicity to host tissues during inflammation.     

Changing Paradigms in Seagrass Restoration

Sharing experiences and results among scientists and managers working on seagrass restoration was the main objective of the first European Seagrass Restoration Workshop that gathered researchers from around Europe. The meeting was the first forum in Europe that allowed for scientists, NGOs, and managers to interact and share their experiences relating to seagrass restoration and management. The results show that none of the seagrass restoration programs developed in Europe by the participants during the last 10 years was successful. Furthermore, an informal review of data published in seagrass restoration success, showed that the results reported were biased because they were mostly based on a very short monitoring period (i.e. < 1 year). Numerous decision trees, guidelines, and restoration models have been developed to aid seagrass restoration management, but the results of this workshop point toward a new paradigm in seagrass restoration were efforts should shift to give priority to natural restoration potential, with an emphasis on the fact that restoration should never be considered the first alternative when planning for the mitigation of coastal development projects or to justify mitigation as a compensation measure for economic activities.     

Different Aquaporin-4 Expression in Glioblastoma Multiforme Patients with and without Seizures

Aquaporin-4 (AQP-4), the most important water channel in the brain, is expressed by astrocyte end feet abutting microvessels. Altered expression levels of AQP-4 and redistribution of the protein throughout the membranes of cells found in glioblastoma multiforme (GBM) lead to development of the edema often found surrounding the tumor mass. Dysregulation of AQP-4 also occurs in hippocampal sclerosis and cortical dysplasia in patients with refractory partial epilepsy. This work reports on analysis of the relationship between AQP-4 expression and the incidence of epileptic seizures in patients with GBM. Immunohistochemical and polymerase chain reaction techniques were used to evaluate AQP-4 in biopsy specimens from 19 patients with GBM, 10 of who had a history of seizures before surgery. AQP-4 mRNA levels were identical in the two groups of patients, but AQP-4 expression was more frequently detected on the GBM membranes from specimens of patients with seizures than from individuals without (10 versus 2, P < 0.001). We conclude that reduced expression of cell surface AQP-4 is characteristic of GBM patients without seizures, likely attributable to a posttranslational mechanism.     

A literature review of the feasibility of glial fibrillary acidic protein as a biomarker for stroke and traumatic brain injury

Traumatic brain injuries (TBIs) are potentially lethal medical conditions, with symptoms that can overlap with symptoms of injuries outside the brain. In many cases, current diagnostic methods do not fully distinguish acute brain injury from other organ damage. In the management of stroke patients, the choice of treatment depends on whether the stroke is ischemic or hemorrhagic; however, no quick lab diagnostic tests are available to distinguish between the two types of strokes. As a result, patient triage, disposition, and patient management decisions may be delayed for patients with suspected TBI and stroke. Glial fibrillary acidic protein (GFAP), a brain-specific biomarker that is released into the blood following TBI and stroke, is being explored for potential diagnostic and prognostic value in these indications. We therefore conducted a review of MEDLINE-indexed publications from 2004 to 2011 to evaluate the current status of GFAP as a prognostic and diagnostic tool for TBI and stroke within the context of current published guidelines. Our review suggests that GFAP could provide clinically valuable information for the prognosis of TBI and stroke, but it is still at an early stage of development as a biomarker. Several TBI studies have shown elevated GFAP levels following a TBI event to be associated with greater severity of injury, poorer outcomes, and increased mortality. Clinical studies also indicate that GFAP has potential clinical utility in the differential diagnosis of various types of stroke. However, more clinical research will be required to determine the ability of GFAP levels to diagnose TBI in heterogeneous patient populations, as well as the ability of GFAP to differentiate between ischemic stroke (IS), intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH), and non-stroke conditions in populations of patients with suspected rather than confirmed stroke. Additional clinical studies will also be required to define the temporal patterns of GFAP release in IS, ICH, SAH, and TBI, and their potential use in the differential diagnosis of these conditions. Finally, such research could demonstrate the ability of GFAP test results to provide unique clinical information that informs management decisions for TBI and stroke patients.     

The -2518 A/G polymorphism in the monocyte chemoattractant protein 1 gene is associated with the risk of developing systemic lupus erythematosus in Argentinean patients: a multicenter study

Systemic lupus erythematosus (SLE) is a systemic, autoimmune disorder. Monocyte chemoattractant protein 1 (MCP-1), a chemokine involved in the recruitment and migration of monocytes/macrophages, has been shown to be increased in the plasma of SLE patients. The aim of our study was to evaluate the possible association of the polymorphism -2518 of the MCP-1 gene with the risk of developing SLE, manifesting lupus nephritis (LN) and with other clinical features of SLE in an Argentinean population. A group of 171 SLE patients and 120 control subjects were examined. Genotypic and allelic frequencies of the MCP-1 -2518 A/G polymorphism showed significant differences between the SLE and the control groups (p=0.001 and p=0.01, respectively). However, the polymorphism showed no association with LN or with the other clinical variables studied. Our results suggest that the presence of the MCP-1 -2518 A/G polymorphism might be a risk factor for developing SLE in genetically predisposed individuals, but it does not seem to have a role in the evolution of the disease in the Argentinean population.     

Identification of four Treponema species in subgingival samples by nested-PCR and their correlation with clinical diagnosis

The relationship between different species of oral Treponemas and inflammation in periodontal disease progression is complex. The purpose of this study was to analyze and compare the subgingival plaque samples collected from periodontally healthy subjects and from chronic gingivitis and periodontitis patients in order to detect the presence of T. denticola, T. pectinovorum, T. socranskii and T. vincentii using nested-PCR technology. After DNA extraction from the samples using QIAmp DNA Mini Kit (QIAGEN, the four Treponema species were determined with nested-polymerase chain reaction which requires two sets of primers to amplify a specific DNA fragment in two separate runs of PCR. Pearson chi-square was implemented to compare the three groups as to the presence of four Treponema species. Results of this investigation showed significant differences between groups regarding subject proportion of T. denticola, T. socranskii, T. pectinovorum, T. vincentii, with a higher percentage of patients from associated-disease groups of patients harboring these four species than healthy subjects. These differences were more pronounced in presence of Treponema denticola and Treponema socranskii. Our findings suggest that Treponema denticola and Treponema socranskii concurrent presence indicate more accurately the association with chronic gingivitis and periodontitis.