C9orf72 poly(PR) mediated neurodegeneration is associated with nucleolar stress.

The ALS/FTD-linked intronic hexanucleotide repeat expansion in the C9orf72 gene is translated into dipeptide repeat proteins, among which poly-proline-arginine (PR) displays the most aggressive neurotoxicity in-vitro and in-vivo . PR partitions to the nucleus when expressed in neurons and other cell types. Using drosophila and primary rat cortical neurons as model systems, we show that by lessening the nuclear accumulation of PR, we can drastically reduce its neurotoxicity. PR accumulates in the nucleolus, a site of ribosome biogenesis that regulates the cell stress response. We examined the effect of nucleolar PR accumulation and its impact on nucleolar function and determined that PR caused nucleolar stress and increased levels of the transcription factor p53. Downregulating p53 levels, either genetically or by increasing its degradation, also prevented PR-mediated neurotoxic phenotypes both in in-vitro and in-vivo models. We also investigated whether PR could cause the senescence phenotype in neurons but observed none. Instead, we found induction of apoptosis via caspase-3 activation. In summary, we uncovered the central role of nucleolar dysfunction upon PR expression in the context of C9-ALS/FTD.

C9orf72 poly(PR) mediated neurodegeneration is associated with nucleolar stress.

The ALS/FTD-linked intronic hexanucleotide repeat expansion in the C9orf72 gene is aberrantly translated in the sense and antisense directions into dipeptide repeat proteins, among which poly proline-arginine (PR) displays the most aggressive neurotoxicity in-vitro and in-vivo. PR partitions to the nucleus when heterologously expressed in neurons and other cell types. We show that by lessening the nuclear accumulation of PR, we can drastically reduce its neurotoxicity. PR strongly accumulates in the nucleolus, a nuclear structure critical in regulating the cell stress response. We determined that, in neurons, PR caused nucleolar stress and increased levels of the transcription factor p53. Downregulating p53 levels also prevented PR-mediated neurotoxicity both in in-vitro and in-vivo models. We investigated if PR could induce the senescence phenotype in neurons. However, we did not observe any indications of such an effect. Instead, we found evidence for the induction of programmed cell death via caspase-3 activation.

Closing the clinical laboratory testing loop with information technology.

Information technology can enhance the effectiveness of the part of the laboratory testing loop that occurs outside of the clinical laboratory. That external component involves the presentation of laboratory results and related information to physicians and the reception of physician requests for follow-up testing. Improvements made in the clinician-computer interface can conceivably enhance the quality of information transfer of this part of the testing loop and thereby improve the effectiveness of the entire loop. Our experience has been that results presentation is easier to address than order reception and that the economic benefits from improved result presentation can be substantial. Improving order reception requires more finesse, especially with the limitations of today's health systems and their information systems in mind. For instance, effective computer-based management of prospectively developed orders (eg, clinical protocols) not only can have a substantial positive impact on test use, but is actually welcomed by clinicians. Application of information technology at the clinician-computer interface has good potential to foster more appropriate use of clinical laboratory resources.

The deployment of a World Wide Web (W3) based medical information system.

The development of Web technologies has revolutionized information dissemination on the Internet. The University of Minnesota Hospital and Clinic's Web Clinical Information System (CIS) demonstrates the use of the Web as an infrastructure for deploying a medical information system at a fraction of the developmental cost of more traditional client server systems. This Web CIS has been deployed since December 1994. It makes available laboratory results, including a radically improved clinical microbiology reporting system, ad hoc laboratory order entry, and an embedded expert system protocol laboratory ordering system. It provides these services to any physician or patient care area with TCP (or SLIP/PPP) connection to our hospital network backbone, whether the client computer is running MS Windows, the Macintosh OS, or X-Windows. A formal evaluation of one of this systems subcomponents, the display of clinical microbiology information, demonstrated a significant savings in clinician time (43% p < .001) and substantial reduction in interpretive errors (0 vs 15 p < .01).