Selective inhibition of Src SH2 by a novel thiol-targeting tricarbonyl-modified inhibitor and mechanistic analysis by (1)H/(13)C NMR spectroscopy

Synthesis of the Src SH2 domain and its application in bioassays for mirror-image screening

Mirror-image screening systems for Src SH2 domain inhibitors were established using a synthetic Src SH2 domain.

Palladium-Catalyzed Ylidyl-Carbonylation of Aryl Halides To Produce α-Acylphosphoranes

An efficient synthesis of α-acylphosphoranes by palladium-catalyzed carbonylation of aryl iodides with carbon monoxide and stabilized phosphonium ylides has been developed. Featuring 44 examples, the protocol displayed a wide substrate scope under mild reaction conditions, showcasing its potential in synthetic organic chemistry.

Chemokine and cytokine levels in inflammatory bowel disease patients

Crohn's disease (CD) and ulcerative colitis (UC), two forms of inflammatory bowel disease (IBD), are chronic, relapsing, and tissue destructive lesions that are accompanied by the uncontrolled activation of effector immune cells in the mucosa. Recent estimates indicate that there are 1.3 million annual cases of IBD in the United States, 50% of which consists of CD and 50% of UC. Chemokines and cytokines play a pivotal role in the regulation of mucosal inflammation by promoting leukocyte migration to sites of inflammation ultimately leading to tissue damage and destruction. In recent years, experimental studies in rodents have led to a better understanding of the role played by these inflammatory mediators in the development and progression of colitis. However, the clinical literature on IBD remains limited. Therefore, the aim of this study was to evaluate systemic concentrations of key chemokines and cytokines in forty-two IBD patients with a range of disease activity compared to levels found in ten healthy donors. We found a significant increase in an array of chemokines including macrophage migration factor (MIF), CCL25, CCL23, CXCL5, CXCL13, CXCL10, CXCL11, MCP1, and CCL21 in IBD patients as compared to normal healthy donors (P<0.05). Further, we also report increases in the inflammatory cytokines IL-16, IFN-γ, IL-1β and TNF-α in IBD patients when compared to healthy donors (P<0.05). These data clearly indicate an increase in circulating levels of specific chemokines and cytokines that are known to modulate systemic level through immune cells results in affecting local intestinal inflammation and tissue damage in IBD patients. Blockade of these inflammatory mediators should be explored as a mechanism to alleviate or even reverse symptoms of IBD.

Stem cells as potential therapeutic targets for inflammatory bowel disease

The incidence and prevalence of Crohn's disease and ulcerative colitis, the two major forms of inflammatory bowel disease (IBD), are rising. According to some estimates >1 million new cases of IBD arise in the United States annually. The conventional therapies available for IBD range from anti-inflammatory drugs to immunosuppressive agents, but these therapies generally fail to achieve satisfactory results due to their side effects. Interest in a new therapeutic option, that is, biological therapy, has gained much momentum recently due to its focus on different stages of the inflammatory process. Stem cell (SC) research has become a new direction for IBD therapy due to our recent understanding of cell populations involved in the pathogenic process. To this end, hematopoietic and mesenchymal stem cells are receiving more attention from IBD investigators. The intestinal environment, with its crypts and niches, supports incoming embryonic and hematopoietic stem cells and allows them to engraft and differentiate. The above findings suggest that, in the future, SC-based therapy will be a promising alternative to conventional therapy for IBD. In this review, we discuss SCs as potential therapeutic targets for future treatment of IBD.

Structure-based design of novel nonpeptide inhibitors of the Src SH2 domain: Phosphotyrosine mimetics exploiting multifunctional group replacement chemistry*

A series of novel nonpeptide inhibitors of the pp60(c-Src) (Src) SH2 domain is described that exploit multifunctional group replacement of the phenylphosphate moiety of phosphotyrosine (pTyr). Relative to an x-ray structure of citrate complexed to the pTyr binding site of the Src SH2 domain, these nonpeptide ligands illustrate the systematic replacement of the phosphate group by multiple nonhydrolyzable, mono- or dianionic functionalities. Specifically, several phenylalanine (Phe) analogs incorporating key 4' and 3' substituents were synthesized and incorporated into a bicyclic benzamide template previously reported (W. C. Shakespeare et al., Proceedings of the National Academy of Science USA, 2000, Vol. 97, pp. 9373-9378). These pTyr mimetics included 4',3'-diphosphono-Phe (Dpp), 4',3'-dicarboxymethyloxy-Phe (Dcp), and 4'-phosphono-3'-carboxymethyloxy-Phe (Cpp). Noteworthy were nonpeptide inhibitors 8-11 that were 5- to 10-fold more potent than the cognate tetrapeptide ligand Ac-pTyr-Glu-Glu-Ile-NH(2) in binding to the Src SH2 domain.

Peptidyl aldehydes as reversible covalent inhibitors of protein tyrosine phosphatases

Protein tyrosine phosphatases (PTPs) are a large family of enzymes that catalyze the hydrolytic removal of the phosphoryl group from phosphotyrosyl (pY) proteins. PTP inhibitors provide potential treatment of human diseases/conditions such as diabetes and obesity as well as useful tools for studying the function of PTPs in signaling pathways. In this work, we have shown that certain aryl-substituted aldehydes act as reversible, slow-binding inhibitors of modest potency against PTP1B, SHP-1, and a dual-specificity phosphatase, VHR. Attachment of the tripeptide Gly-Glu-Glu to the para position of cinnamaldehyde resulted in an inhibitor (Cinn-GEE) of substantially increased potency against all three enzymes (e.g., K(I) = 5.4 microM against PTP1B). The mechanism of inhibition was investigated using Cinn-GEE specifically labeled with (13)C at the aldehyde carbon and (1)H-(13)C heteronuclear single-quantum coherence spectroscopy. While Cinn-GEE alone showed a single cross-peak at delta 9.64 ((1)H) and delta 201 ((13)C), the PTP1B/Cinn-GEE complex showed three distinct cross-peaks at delta 7.6-7.8 ((1)H) and 130-137 ((13)C). Mutation of the catalytic cysteine (Cys-215 in PTP1B) into alanine had no effect on the cross-peaks, whereas mutation of a conserved active-site arginine (Arg-221 in PTP1B) to alanine abolished all three cross-peaks. Similar experiments with Cinn-GEE that had been labeled with (13)C at the benzylic position revealed a change in the hybridization state (from sp(2) to sp(3)) for the benzylic carbon as a result of binding to PTP1B. These results rule out the possibility of a free aldehyde, aldehyde hydrate, or hemithioacetal as the enzyme-bound inhibitor form. Instead, the data are consistent with the formation of an enamine between the aldehyde group of the inhibitor and the guanidine group of Arg-221 in the PTP1B active site. These aldehydes may provide a general core structure that can be further developed into highly potent and specific PTP inhibitors.