Chemical proteomic identification of T-plastin as a novel host cell response factor in HCV infection.

Hepatitis C virus (HCV) infection is the leading cause of chronic liver disease that currently affects at least 170 million people worldwide. Although significant efforts have been focused on discovering inhibitors of a viral polymerase (NS5B) or protease (NS3), strategies to cure HCV infection have been hampered by the limited therapeutic target proteins. Thus, discovery of a novel target remains a major challenge. Here, we report a method that combines transcriptome expression analysis with unbiased proteome reactivity profiling to identify novel host cell response factors in HCV infection. A chemical probe for non-directed proteomic profiling was selected based on genome-wide transcriptome expression analysis after HCV infection, which revealed noticeable alterations related to disulfide bond metabolism. On the basis of this result, we screened the proteome reactivity using chemical probes containing thiol-reactive functional groups and discovered a unique labeling profile in HCV-infected cells. A subsequent quantitative chemical proteomic mapping study led to the identification of a target protein, T-plastin (PLST), and its regulation of HCV replication. Our approach demonstrates both a straightforward strategy for selecting chemical probes to discriminate disease states using a model system and its application for proteome reactivity profiling for novel biomarker discovery.

Unbiased proteomic profiling strategy for discovery of bacterial effector proteins reveals that Salmonella protein PheA is a host cell cycle regulator.

Salmonella utilizes a type III secretion system to inject bacterial effector proteins into the host cell cytosol. Once in the cytosol, these effectors hijack various biochemical pathways to regulate virulence. Despite the importance of effector proteins, especially for understanding host-pathogen interactions, a potentially large number of effectors are yet to be identified. Here, we demonstrate that unbiased chemical proteomic profiling using off-the-shelf fluorescent probes leads to the discovery of a host cell cycle regulator encoded in the Salmonella genome. Our profiling combined with bioinformatic analysis implicates 29 Salmonella as potential effectors. We follow up on the top candidate, chorismate mutase-P/prehenate dehydratase, PheA, and present evidence that PheA is an effector that mimics E2F7 transcription factor of the host cell and promotes G1/S cell cycle arrest. This validates our strategy and opens opportunities for effector identification in the future.

Proteome reactivity profiling for the discrimination of pathogenic bacteria.

Diverse proteome reactivity profiles were obtained using small-molecule electrophiles. Based on the cross-reactivity profile, each protein generated a unique reactivity fingerprint. Here, we report the first proteome reactivity signature-based discrimination of 11 bacteria. Perfect differentiation of 11 bacteria can be achieved using 2 benzyl-halide probes.

Small-molecule probes elucidate global enzyme activity in a proteomic context.

The recent dramatic improvements in high-resolution mass spectrometry (MS) have revolutionized the speed and scope of proteomic studies. Conventional MS-based proteomics methodologies allow global protein profiling based on expression levels. Although these techniques are promising, there are numerous biological activities yet to be unveiled, such as the dynamic regulation of enzyme activity. Chemical proteomics is an emerging field that extends these types proteomic profiling. In particular, activity-based protein profiling (ABPP) utilizes small-molecule probes to monitor enzyme activity directly in living intact subjects. In this mini-review, we summarize the unique roles of small-molecule probes in proteomics studies and highlight some recent examples in which this principle has been applied.

Changes in serum levels of IGF-1 and in growth following adenotonsillectomy in children.

OBJECTIVE: Adenotonsillar hypertrophy can cause upper airway obstruction and may be associated with growth delay in children. The objective of this study was to evaluate the long-term effects of adenotonsillectomy on height, weight, and body mass index (BMI) in children with sleep-disordered breathing (SDB). METHODS: Fifty-two children (mean age 6.2+/-2.3 years) clinically diagnosed with SDB were enrolled. Children were diagnosed and scheduled for adenotonsillectomy (T&A) based on their responses to the validated, 22-item Sleep Related Breathing Disorder (SRDB) scale and a physical examination that showed adenotonsillar hypertrophy. Weight, height, and BMI were evaluated before and 5 years after T&A. Serum levels of insulin-like growth factor-1 (IGF-1) were measured before and 1 month after T&A. RESULTS: Serum levels of IGF-1 were significantly higher at 1 month after T&A compared to before T&A (p<0.001). Thirty children (58%) returned for follow-up testing 5 years later. Their Z scores (standard deviation scores) for weight, height, and BMI of 30 children were significantly higher 5 years after T&A compared to before T&A (p<0.01). CONCLUSION: Children with SDB who undergo adenotonsillectomy show significant, long-term increases in weight, height and BMI, as well as a significant increase in serum levels of IGF-1.

Analysis of unilateral sclerotic temporal bone: how does the sclerosis change the mastoid pneumatization morphologically in the temporal bone?

BACKGROUND: Some disorders, such as otitis media and Eustachian tube dysfunction, may cause the temporal bone to become sclerotic. A sclerotic temporal bone has the tendency to shrink. The aim of this study was to evaluate the morphologic changes that result from sclerosis of the temporal bone. METHODS: We measured 9 variables on 2 axial images, and 8 variables on 2 coronal images in healthy ears and diseased ears in 37 patients with unilateral chronic otitis media. We also measured the volume of mastoid pneumatization. RESULTS: The distance from sigmoid sinus to Henle's spine was correlated to the degree of volume reduction, and it accounted for about 17.7% of the total variation in volume reduction. There was no difference in the sigmoid sinus type in comparisons between sclerotic and pneumatic mastoids. CONCLUSIONS: The sclerosis of the temporal bone was observed to reduce the volume of the mastoid pneumatization. However, a large portion of the volume reduction may result from the sclerotic change in the air cell system, rather than from shrinkage of the mastoid bone. Therefore, the location of surgically-important structures, in the middle and inner ear, is only rarely changed in sclerotic temporal bone.