Inhibition of cyclin-dependent kinase 5 but not of glycogen synthase kinase 3-ß prevents neurite retraction and tau hyperphosphorylation caused by secretable products of human T-cell leukemia virus type I-infected lymphocytes.

Human T-cell leukemia virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurodegenerative disease characterized by selective loss of axons and myelin in the corticospinal tracts. This central axonopathy may originate from the impairment of anterograde axoplasmic transport. Previous work showed tau hyperphosphorylation at T(181) in cerebrospinal fluid of HAM/TSP patients. Similar hyperphosphorylation occurs in SH-SY5Y cells incubated with supernatant from MT-2 cells (HTLV-I-infected lymphocytes secreting viral proteins, including Tax) that produce neurite shortening. Tau phosphorylation at T(181) is attributable to glycogen synthase kinase 3-ß (GSK3-ß) and cyclin-dependent kinase 5 (CDK5) activation. Here we investigate whether neurite retraction in the SH-SY5Y model associates with concurrent changes in other tau hyperphosphorylable residues. Threonine 181 turned out to be the only tau hyperphosphorylated residue. We also evaluate the role of GSK3-ß and CDK5 in this process by using specific kinase inhibitors (LiCl, TDZD-8, and roscovitine). Changes in both GSK3-ß active and inactive forms were followed by measuring the regulatory phosphorylable sites (S(9) and Y(216) , inactivating and activating phosphorylation, respectively) together with changes in ß-catenin protein levels. Our results showed that LiCl and TDZD-8 were unable to prevent MT-2 supernatant-mediated neurite retraction and also that neither Y(216) nor S(9) phosphorylations were changed in GSK3-ß. Thus, GSK3-ß seems not to play a role in T(181) hyperphosphorylation. On the other hand, the CDK5 involvement in tau phosphorylation was confirmed by both the increase in its enzymatic activity and the absence of MT-2 neurite retraction in the presence of roscovitine or CDK5 siRNA transfection.

Application of capillary electrophoresis for the identification of Atlantic salmon and rainbow trout under raw and heat treatment.

Accurate authentication of related species is necessary to prevent the illegal replacement of species of higher quality and/or price with lower-quality, less expensive species. Atlantic salmon (Salmo salar), an expensive and valuable species, can be intentionally substituted with rainbow trout (Oncorhynchus mykiss). Using the technique of capillary zone electrophoresis (CZE), the identification of raw species was based on the analysis of muscle sarcoplasmic (water-soluble) proteins, while for canned species identification was based on muscle proteins solubilized with urea and sodium dodecyl sulfate (SDS). Either water or urea-SDS extracted proteins gave reproducible and distinct electrophoretic patterns of proteins for both species independent of storage conditions. Although data analysis indicated changes in protein profiles for both species during storage, species identification was still possible. In addition, quality determination during refrigerated and frozen storage involved the use of two freshness indexes: K value (the relationship between inosine monophosphate, inosine, and hypoxantine) and pH. A linear correlation was found between changes in electrophoretic patterns and K values for refrigerated salmon species. Trout kept in storage for six days reached a constant K value higher than the maximum limit for a product of good quality, preventing determination of any correlation with electrophoretic pattern. The protein profiles obtained by CZE during long storage revealed their potential for monitoring both differences between fish species and changes in quality during refrigerated, frozen, and canned storage of the species under study.

Microtubule proteins and their post-translational forms in the cerebrospinal fluid of patients with paraparesis associated with HTLV-I infection and in SH-SY5Y cells: an in vitro model of HTLV-I-induced disease.

HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is characterized by axonal degeneration of the corticospinal tracts. The specific requirements for transport of proteins and organelles to the distal part of the long axon are crucial in the corticospinal tracts. Microtubule dysfunction could be involved in this disease, configuring an axonal transport disease. We measured tubulin and its post-translational modified forms (acetylated and tyrosinated) in CSF of patients and controls, as well as tau and its phosphorylated forms. There were no significant differences in the contents of tubulin and acetyl-tubulin between patients and controls; tyrosyl-tubulin was not detected. In HAM/TSP, tau levels were significantly reduced, while the ratio of pT181/total tau was higher in patients than in controls, this being completely different from what is reported in other neurodegenerative diseases. Phosphorylation at T181 was also confirmed by Mass Spectrometry analysis. Western Blotting with monospecific polyclonal antibodies against pS199, pT205, pT231, pS262, pS356, pS396, pS404 and pS422 did not show differences in phosphorylation in these residues between patients and controls. Treating human SH-SY5Y neuroblastoma cells, a well-known in vitro neurite retraction model, with culture supernatant of MT-2 cells (HTLV-I infected cell line that secretes the viral Tax protein) we observed neurite retraction and an increase in tau phosphorylation at T181. A disruption of normal phosphorylation of tau protein in T181 could result in its dysfunction, contributing to axonal damage.

Microtubule proteins and their post-translational forms in the cerebrospinal fluid of patients with paraparesis associated with HTLV-I infection and in SH-SY5Y cells: An in vitro model of HTLV-I-induced disease

HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is characterized by axonal degeneration of the corticospinal tracts. The specific requirements for transport of proteins and organelles to the distal part of the long axon are crucial in the corticospinal tracts. Microtubule dysfunction could beinvolved in this disease, configuring an axonal transport disease. We measured tubulin and its posttranslational modified forms (acetylated and tyrosinated) in CSF of patients and controls, as well as tau and its phosphorylated forms. There were no significant differences in the contents of tubulin and acetyl-tubulinbetween patients and controls; tyrosyl-tubulin was not detected. In HAM/TSP, tau levels were significantly reduced, while the ratio of pT181/total tau was higher in patients than in controls, this being completely different from what is reported in other neurodegenerative diseases. Phosphorylation at T181 was also confirmed by Mass Spectrometry analysis. Western Blotting with monospecific polyclonal antibodies against pS199, pT205, pT231, pS262, pS356, pS396, pS404 and pS422 did not show differences in phosphorylation in these residues between patients and controls. Treating human SH-SY5Y neuroblastoma cells, a well-known in vitro neurite retraction model, with culture supernatant of MT-2 cells (HTLV-I infected cell line that secretes theviral Tax protein) we observed neurite retraction and an increase in tau phosphorylation at T181. A disruptionof normal phosphorylation of tau protein in T181 could result in its dysfunction, contributing to axonal damage.

Trophic factors in cerebrospinal fluid and spinal cord of patients with tropical spastic paraparesis, HIV, and Creutzfeldt-Jakob disease.

HTLV-1-associated myelopathy/tropical spastic paraparesis (TSP/HAM) is a chronic CNS disease characterized by axomyelinic degeneration of the long axons of corticospinal tracts. Levels of NGF, NT-3, NT-4/5, BDNF, GDNF, CNTF, and FGF-2 were measured in the cerebrospinal fluid (CSF) of 21 TSP/HAM patients and 20 controls. NGF, BDNF, and FGF-2 levels were also determined in 19 patients with HIV motor cognitive motor syndrome, and in 21 subjects diagnosed with Creutzfeldt Jakob disease (CJD). No significant differences were detected in the concentrations of NGF, BDNF, NT-3, NT-4/5, GDNF, and CNTF in the CSF between TSP/HAM patients and controls. FGF-2 was significantly lower in the CSF of the three groups of patients compared with controls; the HIV group exhibited the lowest values. HIV patients differed from TSP/HAM in their significantly higher levels of NGF and lower levels of BDNF and FGF-2, whereas CJD patients differed only in their higher levels of NGF. Immunohistochemical studies were done of trophic factors (NGF and FGF-2) and neurotrophin receptors (trkA and p75) in spinal cord and motor cortical areas from anatomopathological cases of TSP/HAM. Results indicated that NGF is expressed in motoneurons and oligodendrocytes of the posterior column of the spinal cord. FGF-2 was detected in motoneurons and spinal cord vessels. p75 receptor was detected in cortical neurons. The absence of a significant change in the trophic factor levels in TSP/HAM may be attributed to a selective axonal lesion in a slow process.

TIMPs and MMPs expression in CSF from patients with TSP/HAM.

The tropical spastic paraparesis or human T-cell lymphotropic virus associated myelopathy (TSP/HAM), has been related with an overexpression of matrix metalloproteinases (MMPs), especially MMP-9. Initial studies of reverse zymography with cerebrospinal fluid (CSF) from TSP/HAM patients, and controls showed the presence of TIMPs, endogenous MMP inhibitors. We determined in CSF the levels of TIMPs by immunoanalysis in 25 patients with TSP/HAM, and compared with two groups: controls and patients with acute and subacute inflammatory neurological diseases. We found that TIMP-2, TIMP-3 and TIMP-4 levels were significantly higher than in controls in both TSP/HAM and inflammatory patients, while TIMP-1 was increased only in the inflammatory group. Levels of MMP-3 and MMP-9 from the two groups of patients showed a significant upregulation in CSF. In the CSF of around the 70% of TSP-HAM and inflammatory patients the presence MMP-9 was detected by zymography, but not in controls. MMP-2 was only overexpressed in the acute inflammatory group. The active form of MMP-2 was observed in both groups of patients with a similar high frequency (60%). MMPs overexpressions are independent of the evolution time of the disease in TSP/HAM. The chronic overexpression of these extracelullar matrix proteins detected in CSF of TSP/HAM should be indirectly produced by secreted viral proteins being responsible for the progression of this disease, accounting for the observed differences with acute inflammatory patients. Our results support the existence of an imbalance between MMPs and their endogenous tissue inhibitors, which could be a pathogenic factor in the chronicity of TSP/HAM.