Nesprin-1alpha self-associates and binds directly to emerin and lamin A in vitro

The mitogen-stimulated protein kinase p70(s6k)/p85(s6k) (S6K) plays an essential role in cell proliferation and growth, with inhibitors of the S6K signalling pathway showing promise as anti-tumour therapeutics. Here, we report that the bisindolylmaleimide derivative Ro 31-6045, previously reported to be inactive as a kinase inhibitor, inhibited S6K activity in vivo with an IC50=8 microM. Structure/function analysis using mutant forms of S6K indicates that Ro 31-6045 inhibition is independent of the upstream activator mTOR. Ro 31-6045 will prove useful in elucidating the complex activation mechanism of S6K and its independence from mTOR will allow confirmation of functional data obtained using the mTOR inhibitor rapamycin.     

Effects of cytotoxic T lymphocytes (CTL) directed against a single simian immunodeficiency virus (SIV) Gag CTL epitope on the course of SIVmac239 infection

Vaccine-induced cytotoxic T lymphocytes (CTL) have been implicated in the control of virus replication in simian immunodeficiency virus (SIV)-challenged and simian-human immunodeficiency virus-challenged macaques. Therefore, we wanted to test the impact that vaccine-induced CTL responses against an immunodominant Gag epitope might have in the absence of other immune responses. By themselves, these strong CTL responses failed to control SIVmac239 replication.     

Tat-vaccinated macaques do not control simian immunodeficiency virus SIVmac239 replication

The regulatory proteins of human immunodeficiency virus may represent important vaccine targets. Here we assessed the role of Tat-specific cytotoxic T lymphocytes (CTL) in controlling pathogenic simian immunodeficiency virus SIVmac239 replication after using a DNA-prime, vaccinia virus Ankara-boost vaccine regimen. Despite the induction of Tat-specific CTL, there was no significant reduction in either peak or viral set point compared to that of controls.     

Effect of phage therapy on the turnover and function of peripheral neutrophils

The aim of this investigation was to establish the impact of phage therapy on the turnover and function of circulating neutrophils in 37 patients with suppurative bacterial infections. We determined the levels of circulating neutrophils and their precursors before therapy, after 3 weeks of therapy, and at a distant time interval (3 months) following the beginning of therapy. In addition, we measured the ability of neutrophils to phagocytize Staphylococcus aureus in vitro. Eight healthy blood donors served as a control group. The results showed that, among the studied parameters, the significant changes involved neutrophil precursor count and the ability of neutrophils to phagocytize bacteria. The percentage of neutrophils in patients before therapy was lower than in healthy donors (mean 58.0, versus 61.4). This value dropped further in patients after 3 months of following the therapy (mean 55.6). The content of neutrophil precursors, on the other hand, was lower in healthy donors than in patients before therapy (mean 2.5, versus 3.8). After 3 weeks of the therapy and after 3 months, the levels of neutrophil precursors were significantly higher (mean 4.8 and 4.9, respectively) than in control donors. The phagocytic index was lower in patients before therapy than in control donors (mean 66.3, versus 70.1) and decreased further after 3 weeks of therapy (mean 59.0) and after 3 months (mean 59.6). The results of this investigation indicate that successful phage therapy accelerates the turnover of neutrophils, accompanied by a decrease in their ability to phagocytize bacteria.     

Tissue localization of TGFα and apoptosis are inversely related in colorectal tumors

Expression of TGFalpha and the EGF receptor was studied in relation to apoptosis in human colorectal mucosa and premalignant and malignant tumors. In normal mucosa the proteins colocalized both in the proliferation compartment and at the luminal pole of the crypts in cells committed to undergo apoptosis. While staining for the EGF receptor was increased in premalignant and malignant lesions, TGFalpha was undetectable in aberrant crypt foci as well as large areas of adenomas. Incidence of apoptosis (AI) was high in these areas ranging from 8.83-24.59. Adenomas did, however, contain islands of high TGFalpha expression where AI was decreased to a range of 0.76-4.00 (decreased at P=0.0027). In carcinomas TGFalpha expression was increased above both normal and adenoma levels corresponding to the decrease in apoptosis in the malignant tumors. Tissue localization of TGFalpha and AI were still inversely related ( P=0.022), but interpatient variability was much larger than for adenomas. The data indicate that TGFalpha is the main survival factor in premalignant tumor cells of the colon, while additional factors moderate its effect in carcinomas. This suggests the possibility of targeting the EGF receptor pathway not only for treatment but also for the reversal of adenoma growth and the prevention of malignant colorectal tumors.     

Monoclonal antibodies as therapeutics in oncology

The specificity of antibodies has been harnessed to target cancer cells and the first therapeutic antibodies for use in oncology are now finding application in the clinic. Studies are currently under way to develop new and improved antibodies. Recent developments have been made in the identification of novel targets, including the use of genomic and proteomic technologies. Several methods are also being developed to enhance antibody efficacy.     

Mice deficient in small leucine-rich proteoglycans: novel in vivo models for osteoporosis,osteoarthritis, Ehlers-Danlos syndrome,muscular dystrophy,and corneal diseases

Small leucine-rich proteoglycans (SLRPs) are extracellular molecules that bind to TGFbetas and collagens and other matrix molecules. In vitro, SLRPs were shown to regulate collagen fibrillogenesis, a process essential in development, tissue repair, and metastasis. To better understand their functions in vivo, mice deficient in one or two of the four most prominent and widely expressed SLRPs (biglycan, decorin, fibromodulin, and lumican) were recently generated. All four SLRP deficiencies result in the formation of abnormal collagen fibrils. Taken together, the collagen phenotypes demonstrate a cooperative, sequential, timely orchestrated action of the SLRPs that altogether shape the architecture and mechanical properties of the collagen matrix. In addition, SLRP-deficient mice develop a wide array of diseases (osteoporosis, osteoarthritis, muscular dystrophy, Ehlers-Danlos syndrome, and corneal diseases), most of them resulting primarily from an abnormal collagen fibrillogenesis. The development of these diseases by SLRP-deficient mice suggests that mutations in SLRPs may be part of undiagnosed predisposing genetic factors for these diseases. Although the distinct phenotypes developed by the different singly deficient mice point to distinct in vivo function for each SLRP, the analysis of the double-deficient mice also demonstrates the existence of rescuing/compensation mechanisms, indicating some functional overlap within the SLRP family.     

Huntingtin fragments that aggregate go their separate ways

N-terminal region of mutant huntingtin forms intranuclear and cytoplasmic aggregates in neurons that may contribute to neuronal death in Huntington's disease. show that different endoprotease-cleaved huntingtin fragments form nuclear and cytoplasmic inclusions.