Kettering University

About: Kettering University is a education organization based out in Flint, Michigan, United States. It is known for research contribution in the topics: RNA & Antigen. The organization has 6842 authors who have published 7689 publications receiving 337503 citations. The organization is also known as: GMI Engineering & Management Institute & General Motors Institute.

Molecular Characterization of Pediatric Gastrointestinal Stromal Tumors

Abstract: Purpose: Pediatric gastrointestinal stromal tumors (GIST) are rare and occur preferentially in females as multifocal gastric tumors, typically lacking mutations in KIT and PDGFRA . As KIT oncoprotein is consistently overexpressed in pediatric GIST, we sought to investigate the activation of KIT downstream targets and alterations of KIT/PDGFRA gene copy number, mine novel therapeutic targets by gene expression, and test tyrosine kinase receptor activation by proteomic profiling. Experimental Design: Seventeen pediatric GISTs were investigated for KIT/PDGFRA genotype and biochemical activation of KIT downstream targets. The transcriptional profile of 13 nodules from 8 pediatric patients was compared with 8 adult wild-type (WT) GISTs, including 3 young adults. The drug sensitivity of second-generation kinase inhibitors was tested in murine Ba/F3 cells expressing human WT KIT, as well as in short-term culture of explants of WT GIST cells. Results: A KIT/PDGFRA WT genotype was identified in all 12 female patients, whereas two of five males had either a KIT exon 11 or PDGFRA exon 18 mutation. KIT downstream targets were consistently activated. Pediatric GISTs showed a distinct transcriptional signature, with overexpression of BAALC, PLAG1, IGF1R, FGF4 , and NELL1. In vitro studies showed that nilotinib, sunitinib, dasatinib, and sorafenib are more effective than imatinib against WT KIT. Conclusions: Rare cases of pediatric GIST may occur in male patients and harbor activating KIT/PDGFRA mutations. Pediatric GISTs show distinct transcriptional signature, suggesting a different biology than WT GIST in adults. In vitro drug screening showed that second-generation kinase inhibitors may provide greater clinical benefit in pediatric GIST.

Initiation of meiotic recombination by formation of DNA double-strand breaks: mechanism and regulation

Abstract: Homologous recombination is essential for accurate chromosome segregation during meiosis in most sexual organisms. Meiotic recombination is initiated by the formation of DSBs (DNA double-strand breaks) made by the Spo11 protein. We review here recent findings pertaining to protein-protein interactions important for DSB formation, the mechanism of an early step in the processing of Spo11-generated DSBs, and regulation of DSB formation by protein kinases.

Deriving human ENS lineages for cell therapy and drug discovery in Hirschsprung disease

Abstract: The enteric nervous system (ENS) is the largest component of the autonomic nervous system, with neuron numbers surpassing those present in the spinal cord. The ENS has been called the 'second brain' given its autonomy, remarkable neurotransmitter diversity and complex cytoarchitecture. Defects in ENS development are responsible for many human disorders including Hirschsprung disease (HSCR). HSCR is caused by the developmental failure of ENS progenitors to migrate into the gastrointestinal tract, particularly the distal colon. Human ENS development remains poorly understood owing to the lack of an easily accessible model system. Here we demonstrate the efficient derivation and isolation of ENS progenitors from human pluripotent stem (PS) cells, and their further differentiation into functional enteric neurons. ENS precursors derived in vitro are capable of targeted migration in the developing chick embryo and extensive colonization of the adult mouse colon. The in vivo engraftment and migration of human PS-cell-derived ENS precursors rescue disease-related mortality in HSCR mice (Ednrb(s-l/s-l)), although the mechanism of action remains unclear. Finally, EDNRB-null mutant ENS precursors enable modelling of HSCR-related migration defects, and the identification of pepstatin A as a candidate therapeutic target. Our study establishes the first, to our knowledge, human PS-cell-based platform for the study of human ENS development, and presents cell- and drug-based strategies for the treatment of HSCR.

Prp22, a DExH-box RNA helicase, plays two distinct roles in yeast pre-mRNA splicing

Abstract: In order to assess the role of Prp22 in yeast pre-mRNA splicing, we have purified the 130 kDa Prp22 protein and developed an in vitro depletion/reconstitution assay. We show that Prp22 is required for the second step of actin pre-mRNA splicing. Prp22 can act on pre-assembled spliceosomes that are arrested after step 1 in an ATP-independent fashion. The requirement for Prp22 during step 2 depends on the distance between the branchpoint and the 3' splice site, suggesting a previously unrecognized role for Prp22 in splice site selection. We characterize the biochemical activities of Prp22, a member of the DExH-box family of proteins, and we show that purified recombinant Prp22 protein is an RNA-dependent ATPase and an ATP-dependent RNA helicase. Prp22 uses the energy of ATP hydrolysis to effect the release of mRNA from the spliceosome. Thus, Prp22 has two distinct functions in yeast pre-mRNA splicing: an ATP-independent role during the second catalytic step and an ATP-requiring function in disassembly of the spliceosome.