CXCR4 Recognition by L- and D-Peptides Containing the Full-Length V3 Loop of HIV-1 gp120.

Human immunodeficiency virus-1 (HIV-1) recognizes one of its principal coreceptors, CXC chemokine receptor 4 (CXCR4), on the host cell via the third variable loop (V3 loop) of HIV-1 envelope glycoprotein gp120 during the viral entry process. Here, the mechanism of the molecular recognition of HIV-1 gp120 V3 loop by coreceptor CXCR4 was probed by synthetic peptides containing the full-length V3 loop. The two ends of the V3 loop were covalently linked by a disulfide bond to form a cyclic peptide with better conformational integrity. In addition, to probe the effect of the changed side-chain conformations of the peptide on CXCR4 recognition, an all-D-amino acid analog of the L-V3 loop peptide was generated. Both of these cyclic L- and D-V3 loop peptides displayed comparable binding recognition to the CXCR4 receptor, but not to another chemokine receptor, CCR5, suggesting their selective interactions with CXCR4. Molecular modeling studies revealed the important roles played by many negative-charged Asp and Glu residues on CXCR4 that probably engaged in favorable electrostatic interactions with the positive-charged Arg residues present in these peptides. These results support the notion that the HIV-1 gp120 V3 loop-CXCR4 interface is flexible for ligands of different chiralities, which might be relevant in terms of the ability of the virus to retain coreceptor recognition despite the mutations at the V3 loop.

Development of small molecule inhibitors targeting TGF-ß ligand and receptor: Structures, mechanism, preclinical studies and clinical usage.

Transforming growth factor-ß (TGF-ß) is a member of a superfamily of pleiotropic proteins that regulate multiple cellular processes such as growth, development and differentiation. Following binding to type I and II TGF-ß serine/threonine kinase receptors, TGF-ß activates downstream signaling cascades involving both SMAD-dependent and -independent pathways. Aberrant TGF-ß signaling is associated with a variety of diseases, such as fibrosis, cardiovascular disease and cancer. Hence, the TGF-ß signaling pathway is recognized as a potential drug target. Various organic molecules have been designed and developed as TGF-ß signaling pathway inhibitors and they function by either down-regulating the expression of TGF-ß or by inhibiting the kinase activities of the TGF-ß receptors. In this review, we discuss the current status of research regarding organic molecules as TGF-ß inhibitors, focusing on the biological functions and the binding poses of compounds that are in the market or in the clinical or pre-clinical phases of development.

[The initial CT findings in patients suffering from invasive pulmonary aspergillosis].

OBJECTIVE: To approach the initial CT findings of invasive pulmonary aspergillosis (IPA) in patients with immunosuppression. METHODS: All consecutive adult patients who met the diagnostic criteria of the 2008 European Organization for Research and Treatment of Cancer/ Mycoses Study Group (EORTC/MSG) for proven or probable IPA were included as of January 2005 to June 2011. The patients were divided into two groups according to patients with or without hematological malignancy. The initial CT findings in our study were retrospectively reviewed by two thoracic radiologists, while patients' demographics and clinical outcomes were blinded. The pattern and number of abnormalities were recorded. RESULTS: A total of 65 IPA patients were eligible, with 34 hematological malignancy patients and 31 non-hematological patients. Among all IPA patients, the pattern of ground-glass opacity and consolidation or mass formation was most commonly seen (56.9%), followed by macronodules (46.2%); halo sign (32.3%) was relatively uncommon. Ground-glass opacity and consolidation or mass formation were more commonly identified in non-hematological patients than in hematological malignancy patients (54.8%, 45.2% vs. 8.8%, both P<0.05), but macronodules, infarct-shaped macronodules and halo signs were less frequently identified in the non-hematological group (16.1%, 3.2%, 12.9%, respectively) than in the hematological malignancy group (73.5%, 23.5% and 50.0%, respectively, P<0.05 or P<0.01). The airway-invasive form of IPA was more frequently seen in non-hematological patients (67.8%), whereas the angioinvasive form was more common in hematological malignancy patients (64.7%, P<0.01). CONCLUSION: Our data indicate that CT findings of IPA in non-hematological patients more commonly present as the airway-invasive form, manifesting ground-glass opacity and consolidation or mass formation, whereas in patients with hematological malignancy it more likely shows evidence of the angioinvasive form with macronodules and halo signs.