Induction of tumor necrosis factor alpha in human neuronal cells by extracellular human T-cell lymphotropic virus type 1 Tax.

To examine the role of human T-lymphotropic virus type 1 (HTLV-1) Tax1 in the development of neurological disease, we studied the effects of extracellular Tax1 on gene expression in NT2-N cells, postmitotic cells that share morphologic, phenotypic, and functional features with mature human primary neurons. Treatment with soluble HTLV-1 Tax1 resulted in the induction of tumor necrosis factor alpha (TNF-alpha) gene expression, as detected by reverse-transcribed PCR and by enzyme-linked immunosorbent assay. TNF-alpha induction was completely blocked by clearance with anti-Tax1 monoclonal antibodies. Furthermore, cells treated with either a mock bacterial extract or with lipopolysaccharide produced no detectable TNF-alpha. Synthesis of TNF-alpha in response to soluble Tax1 occurred in a dose-dependent fashion between 0.25 and 75 nM and peaked within 6 h of treatment. Interestingly, culturing NT2-N cells in the presence of soluble Tax1 for as little as 5 min was sufficient to result in TNF-alpha production, indicating that the induction of TNF-alpha in NT2-N does not require Tax1 to be continually present in the culture medium. Treatment of the undifferentiated parental embryonal carcinoma cell line NT2 with soluble Tax1 did not result in TNF-alpha synthesis, suggesting that differentiation-dependent, neuron-specific factors may be required. These results provide the first experimental evidence that neuronal cells are sensitive to HTLV-1 Tax1 as an extracellular cytokine, with a potential role in the pathology of HTLV-1-associated/tropical spastic paraparesis.     

Bioactive Molecules Derived from Snake Venoms with Therapeutic Potential for the Treatment of Thrombo-Cardiovascular Disorders Associated with COVID-19

The Protein Journal - As expected, several new variants of Severe Acute Respiratory Syndrome-CoronaVirus-2 (SARS-CoV-2) emerged and have been detected around the world throughout this Coronavirus...     

Automatic methods for characterization of sexual dimorphism of adult femora: distal femur

Quantifying sex differences in femoral size and shape has extensive applications in forensics and prosthesis design. By applying strong statistical techniques such as principal component analysis (PCA), certain three-dimensional (3D) morphological variations of adult femora can be quantified over various femoral sizes. Coupling this statistical approach with a novel feature generation and extraction technique, localization of statistically significant (p < 0.05) features are automatically defined and measured. Also, predefined anatomical landmarks and surgical axes have been calculated automatically. In all methods, femoral scale is controlled as a possible parameter of shape. By extensively comparing measurements across 92 male and 74 female femora, the dimorphic characteristics of the distal femur are shown. These differences have not been accounted for in many prosthetic systems and consequently these systems have limited sizing accuracy.     

Bacillus anthracis-derived nitric oxide induces protein S-nitrosylation contributing to macrophage death

Bacillus anthracis, a causative agent of anthrax, is able to germinate and survive within macrophages. A recent study suggested that B. anthracis-derived nitric oxide (bNO) is a key aspect of bacterial defense that protects bacterial DNA from oxidative burst in the macrophages. However, the virulent effect of bNO in host cells has not been investigated. Here, we report that bNO contributes macrophage killing by S-nitrosylation of bioenergetic-relating proteins within mitochondria. Toxigenic Sterne induces expression of the bnos gene and produces bNO during early stage of infection. Nitroso-proteomic analysis coupled with a biotin-switch technique demonstrated that toxigenic infection induces protein S-nitrosylation in B. anthracis-susceptible RAW264.7. For each target enzyme tested (complex I, complex III and complex IV), infection by B. anthracis Sterne caused enzyme inhibition. Nω-nitro-l-arginine methyl ester, a NO synthase inhibitor, reduced S-nitrosylation and partially restored cell viability evaluated by intracellular ATP levels in macrophages. Our data suggest that bNO leads to energy depletion driven by impaired mitochondrial bioenergetic machinery that ultimately contributes to macrophage death. This novel mechanism of anthrax pathogenesis may offer specific approach to the development of therapeutics.     

Identifying the membrane proteome of HIV-1 latently infected cells

Profiling integral plasma membrane proteins is of particular importance for the identification of new biomarkers for diagnosis and for drug development. We report in this study the identification of surface markers by performing comparative proteomics of established human immunodeficiency virus-1 (HIV-1) latent cell models and parental cell lines. To this end we isolated integral membrane proteins using a biotin-directed affinity purification method. Isolated proteins were separated by two-dimensional gel electrophoresis and identified by matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) after in gel digestion. Seventeen different proteins were found to vary on the surface of T-cells due to HIV-1 infection. Of these proteins, 47% were integral membrane proteins, and 18% were membrane-associated. Through the use of complementary techniques such as Western blotting and fluorescent staining, we confirmed the differential expression of some of the proteins identified by MALDI-TOF including Bruton's tyrosine kinase and X-linked inhibitor of apoptosis. Finally, using phosphatidylinositol 3-kinase inhibitors and flavopiridol to inhibit Bruton's tyrosine kinase localization at the membrane and X-linked inhibitor of apoptosis protein expression, respectively, we showed that HIV-1 latently infected cells are more sensitive to these drugs than uninfected cells. This suggests that HIV-1 latently infected cells may be targeted with drugs that alter several pathways that are essential for the establishment and maintenance of latency.     

Paradoxical effects of a stress signal on pro- and anti-apoptotic machinery in HTLV-1 tax expressing cells

Adult T-cell leukemia (ATL) and HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) are associated with Human T-cell lymphotropic virus type 1 (HTLV-1) infection. The viral transactivator, Tax is able to mediate the cell cycle progression by targeting key regulators of the cell cycle such as p21/waf1, p16/ink4a, p53, cyclins D1-3/cdk complexes, and the mitotic spindle checkpoint MAD apparatus, thereby deregulating cellular DNA damage and checkpoint control. Genome expression profiling of infected cells exemplified by the development of DNA microarrays represents a major advance in genome-wide functional analysis. Utilizing cDNA microarray analysis, we have observed an apparent opposing and paradoxical regulatory network of host cell gene expression upon the introduction of DNA damage stress signal. We find the apparent induction of cell cycle inhibitors, and pro- as well as anti-apoptotic gene expression is directly linked to whether cells are at either G1, S, or G2/M phases of the cell cycle. Specifically, a G1/S block is induced by p21/waf1 and p16/ink4a, while pro-apoptotic expression at S, and G2/M is associated with caspase activation, and anti-apoptotic gene expression is associated with up regulation of Bcl-2 family member, namely bfl-1 gene. Therefore, the microarray results indicating expression of both pro- and anti-apoptotic genes could easily be explained by the particular stage of the cell cycle. Mechanism and the functional outcome of induction for both pathways are discussed.