Astrocytic TIMP-1 regulates production of Anastellin, an inhibitor of oligodendrocyte differentiation and FTY720 responses

Astrocyte activation is associated with neuropathology and the production of tissue inhibitor of metalloproteinase-1 (TIMP1). TIMP1 is a pleiotropic extracellular protein that functions both as a protease inhibitor and as a growth factor. Astrocytes that lack expression of Timp1 do not support rat oligodendrocyte progenitor cell (rOPC) differentiation, and adult global Timp1 knockout (Timp1KO) mice do not efficiently remyelinate following a demyelinating injury. Here, we performed an unbiased proteomic analysis and identified a fibronectin-derived peptide called Anastellin (Ana) that was unique to the Timp1KO astrocyte secretome. Ana was found to block rOPC differentiation in vitro and enhanced the inhibitory influence of fibronectin on rOPC differentiation. Ana is known to act upon the sphingosine-1-phosphate receptor 1, and we determined that Ana also blocked the pro-myelinating effect of FTY720 (or fingolimod) on rOPC differentiation in vitro. Administration of FTY720 to wild-type C57BL/6 mice during MOG35-55-experimental autoimmune encephalomyelitis ameliorated clinical disability while FTY720 administered to mice lacking expression of Timp1 (Timp1KO) had no effect. Analysis of Timp1 and fibronectin (FN1) transcripts from primary human astrocytes from healthy and multiple sclerosis (MS) donors revealed lower TIMP1 expression was coincident with elevated FN1 in MS astrocytes. Last, analyses of proteomic databases of MS samples identified Ana peptides to be more abundant in the cerebrospinal fluid (CSF) of human MS patients with high disease activity. A role for Ana in MS as a consequence of a lack of astrocytic TIMP-1 production could influence both the efficacy of fingolimod responses and innate remyelination potential in the MS brain.

Astrocytic TIMP-1 regulates production of Anastellin, a novel inhibitor of oligodendrocyte differentiation and FTY720 responses

Astrocyte activation is associated with neuropathology and the production of tissue inhibitor of metalloproteinase-1 (TIMP1). TIMP1 is a pleiotropic extracellular protein that functions both as a protease inhibitor and as a growth factor. We have previously demonstrated that murine astrocytes that lack expression of Timp1 do not support rat oligodendrocyte progenitor cell (rOPC) differentiation, and adult global Timp1 knockout ( Timp1 KO ) mice do not efficiently remyelinate following a demyelinating injury. To better understand the basis of this, we performed unbiased proteomic analyses and identified a fibronectin-derived peptide called anastellin that is unique to the murine Timp1 KO astrocyte secretome. Anastellin was found to block rOPC differentiation in vitro and enhanced the inhibitory influence of fibronectin on rOPC differentiation. Anastellin is known to act upon the sphingosine-1-phosphate receptor 1 (S1PR1), and we determined that anastellin also blocked the pro-myelinating effect of FTY720 (or fingolimod) on rOPC differentiation in vitro . Further, administration of FTY720 to wild-type C57BL/6 mice during MOG 35-55 -EAE ameliorated clinical disability while FTY720 administered to mice lacking expression of Timp1 in astrocytes ( Timp1 cKO ) had no effect. Analysis of human TIMP1 and fibronectin ( FN1 ) transcripts from healthy and multiple sclerosis (MS) patient brain samples revealed an inverse relationship where lower TIMP1 expression was coincident with elevated FN1 in MS astrocytes. Lastly, we analyzed proteomic databases of MS samples and identified anastellin peptides to be more abundant in the cerebrospinal fluid (CSF) of human MS patients with high versus low disease activity. The prospective role for anastellin generation in association with myelin lesions as a consequence of a lack of astrocytic TIMP-1 production could influence both the efficacy of fingolimod responses and the innate remyelination potential of the the MS brain.

Significance Statement

Astrocytic production of TIMP-1 prevents the protein catabolism of fibronectin. In the absence of TIMP-1, fibronectin is further digested leading to a higher abundance of anastellin peptides that can bind to sphingosine-1-phosphate receptor 1. The binding of anastellin with the sphingosine-1-phosphate receptor 1 impairs the differentiation of oligodendrocytes progenitor cells into myelinating oligodendrocytes in vitro , and negates the astrocyte-mediated therapeutic effects of FTY720 in the EAE model of chronic CNS inflammation. These data indicate that TIMP-1 production by astrocytes is important in coordinating astrocytic functions during inflammation. In the absence of astrocyte produced TIMP-1, elevated expression of anastellin may represent a prospective biomarker for FTY720 therapeutic responsiveness.

Direct application of Etest to gram-positive cocci from blood cultures: quick and reliable minimum inhibitory concentration data

The Etest was applied directly to 100 Gram-positive bacterial strains from blood cultures to measure their minimum inhibitory concentration (MIC). Results showed 100% concordance of MIC data between a direct Etest method and the standard Etest method for Streptococcus pneumoniae, beta-hemolytic streptococci, and viridans group streptococci. In addition, direct Etest for Staphylococcus aureus, coagulase negative staphylococci, Enterococcus faecium, and Enterococcus faecalis showed 83 to 100% correlation with standard Etests. These data indicate that the Etest is useful to obtain MIC data on Gram-positive cocci (especially streptococci) directly from positive blood cultures. The advantages of a direct Etest are two fold: MIC results can be obtained 24 hours earlier than standard methods and a more representative population of the bacterial isolate is tested.

An investigation of solvent-induced neuro-psychiatric disorders in spray painters

An index case of chronic toxic encephalopathy is described in a 28 year old male spray painter with eleven years of exposure to solvents at work. The patient had progressive affective symptoms following repeated past episodes suggestive of acute solvent intoxication. He also showed impaired performance on tests of auditory memory, perceptual speed, visual scanning, and manual dexterity, as well as electromyographic evidence of prolongation of distal terminal latency and slowing of conduction velocities. The case investigation was followed up with an epidemiological study of the factory where he worked, to determine if other spray painters might have similar excessive complaints of neuropsychiatric symptoms and/or objective neurobehavioural deficits. This involved 15 other male spray painters employed for at least five years, and a sex- and age-matched group of 15 control workers not exposed to solvents. The spray painters reported significantly more numbers of neurobehavioural symptoms than the controls. There were little differences in neurobehavioural test results, except for aiming test (psychomotor co-ordination) and Benton visual retention test (visual memory). Spray painters with four or more neurobehavioural symptoms also performed more poorly on Digit Symbol (perceptual speed) compared with those with less number of symptoms. The epidemiological results provide strong circumstantial basis for the diagnosis of chronic toxic encephalopathy in the patient, and also indicates a need for vigilance of the hazards of central nervous system disorders in workers with chronic exposure to solvents in Singapore.

Breast angiosarcoma metastatic to the maxillary gingiva. Case report

A case of breast angiosarcoma metastatic to the maxillary gingiva is reported. A review of the literature revealed only three previously reported cases. Angiosarcomas often present as benign lesions. The surgeon should maintain a high level of vigilance when patients present with oral lesions and a history of breast tumor.

Intermaxillary fixation using screws. Report of a technique

A technique of intermaxillary fixation using screws anchored in the maxilla and mandible has been described. AO (Synthes) screws with a diameter of 3.5 mm and 12 mm to 16 mm in length were inserted at the antero-lateral surface of the maxilla and the buccal surface of the mandible. This technique is particularly suitable for mandibular fractures in denture wearing patients.