Novel ß- and γ-Amino Acid-Derived Inhibitors of Prostate-Specific Membrane Antigen.

Prostate-specific membrane antigen (PSMA) is an excellent biomarker for the early diagnosis of prostate cancer progression and metastasis. The most promising PSMA-targeted agents in the clinical phase are based on the Lys-urea-Glu motif, in which Lys and Glu are α-(l)-amino acids. In this study, we aimed to determine the effect of ß- and γ-amino acids in the S1 pocket on the binding affinity for PSMA. We synthesized and evaluated the ß- and γ-amino acid analogues with (S)- or (R)-configuration with keeping α-(l)-Glu as the S1'-binding pharmacophore. The structure-activity relationship studies identified that compound 13c, a ß-amino acid analogue with (R)-configuration, exhibited the most potent PSMA inhibitory activity with an IC50 value of 3.97 nM. The X-ray crystal structure of PSMA in complex with 13c provided a mechanistic basis for the stereochemical preference of PSMA, which can guide the development of future PSMA inhibitors.

A pathogen-derived metabolite induces microglial activation via odorant receptors.

Microglia (MG), the principal neuroimmune sentinels in the brain, continuously sense changes in their environment and respond to invading pathogens, toxins, and cellular debris, thereby affecting neuroinflammation. Microbial pathogens produce small metabolites that influence neuroinflammation, but the molecular mechanisms that determine whether pathogen-derived small metabolites affect microglial activation of neuroinflammation remain to be elucidated. We hypothesized that odorant receptors (ORs), the largest subfamily of G protein-coupled receptors, are involved in microglial activation by pathogen-derived small metabolites. We found that MG express high levels of two mouse ORs, Olfr110 and Olfr111, which recognize a pathogenic metabolite, 2-pentylfuran, secreted by Streptococcus pneumoniae. These interactions activate MG to engage in chemotaxis, cytokine production, phagocytosis, and reactive oxygen species generation. These effects were mediated through the Gαs -cyclic adenosine monophosphate-protein kinase A-extracellular signal-regulated kinase and Gßγ -phospholipase C-Ca2+ pathways. Taken together, our results reveal a novel interplay between the pathogen-derived metabolite and ORs, which has major implications for our understanding of microglial activation by pathogen recognition. DATABASE: Model data are available in the PMDB database under the accession number PM0082389.

Author Correction: Structure-Activity Relationships of Baicalein and its Analogs as Novel TSLP Inhibitors.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Design and synthesis of a novel BODIPY-labeled PSMA inhibitor.

Prostate-specific membrane antigen (PSMA) is a zinc-bound metalloprotease which is highly expressed in metastatic prostate cancer. It has been considered an excellent target protein for prostate cancer imaging and targeted therapy because it is a membrane protein and its active site is located in the extracellular region. We successfully synthesized and evaluated a novel PSMA ligand conjugated with BODIPY650/665. Compound 1 showed strong PSMA-inhibitory activity and selective uptake into PSMA-expressing tumors. Compound 1 has the potential to be utilized as a near infrared (NIR) optical imaging probe targeting PSMA-expressing cancers.

Structure-Activity Relationships of Baicalein and its Analogs as Novel TSLP Inhibitors.

Thymic stromal lymphopoietin (TSLP) plays an important role in the differentiation and proliferation of Th2 cells, resulting in eosinophilic inflammation and numerous allergic diseases. Baicalein (1), a major component of Scutellaria baicalensis, was found to be the first small molecule to block TSLP signaling pathways. It inhibited effectively eosinophil infiltration in house dust mite-induced and ovalbumin-challenged mouse models. Structure-activity relationship studies identified compound 11a, a biphenyl flavanone analog, as a novel human TSLP inhibitor for the discovery and development of new anti-allergic drugs.

Design and synthesis of dye-conjugated hepsin inhibitors.

Hepsin is a type II serine protease that is highly expressed in neoplastic prostate. It is an attractive biomarker for imaging metastatic prostate cancer because of its overexpression in advanced prostate cancer and the location of its active site on the cell surface. We designed and synthesized novel hepsin-targeted imaging probes by conjugating the hepsin-binding ligand with near-infrared (NIR) optical dyes. The Leu-Arg dipeptides, attached to BODIPY or SulfoCy7, exhibited strong hepsin-inhibitory activities with Ki values of 21 and 22 nM, respectively. Compound 2 showed selective uptake and retention in hepsin-overexpressing cells. This is the first report of hepsin-targeted optical probes with strong binding affinities and high selectivity over matriptase. Compound 2 has the potential to be used for developing hepsin-based imaging probes and be as a prototype molecule in the design of new hepsin inhibitors.

18F-Labeled BODIPY Dye: A Potential Prosthetic Group for Brain Hybrid PET/Optical Imaging Agents.

There are few hybrid positron emission tomography (PET)/fluorescence imaging agents available for brain imaging. For this purpose, BODIPY dye is very attractive because one of its fluorine atoms can be readily exchanged with 18F, and it can be modified to produce red-shifted fluorescence. In this study, therefore, we synthesized and investigated a 18F-labeled red-shifted BODIPY dye as a prosthetic group for brain hybrid PET/optical imaging agents and determined the optimal dose of this radioligand for hybrid imaging. The red-shifted BODIPY dye (1) was synthesized, and one of its fluorine atoms was exchanged with 18F using SnCl4 in high yield. Partition coefficients of 18F-labeled BODIPY dye ([18F]1) and 1 were measured using its radioactivity and fluorescence, respectively, which were shown to be suitable for brain penetration. Optimal dose for hybrid imaging was determined by analysis of PET/CT and optical images of Balb/C nude mice injected with [18F]1 and 1, respectively. Hybrid PET/optical images of mice injected with optimal dose of [18F]1 showed strong radioactivity and fluorescence signal in the brain at 2 min after injection, with rapid clearance by 30 min. Tissue distribution data confirmed the in vivo and ex vivo PET/optical imaging data, indicating desirable brain pharmacokinetics of the radioligand. Taken together, the results of this study suggest that [18F]1 can be widely used as a prosthetic group for brain hybrid PET/optical imaging agents.

Reconstruction of the lower extremity using free flaps.

BACKGROUND: The aim of lower-extremity reconstruction has focused on wound coverage and functional recovery. However, there are limitations in the use of a local flap in cases of extensive defects of the lower-extremities. Therefore, free flap is a useful option in lower-extremity reconstruction. METHODS: We performed a retrospective review of 49 patients (52 cases) who underwent lower-extremity reconstruction at our institution during a 10-year period. In these patients, we evaluated causes and sites of defects, types of flaps, recipient vessels, types of anastomosis, survival rate, and complications. RESULTS: There were 42 men and 10 women with a mean age of 32.7 years (range, 3-72 years). The sites of defects included the dorsum of the foot (19), pretibial area (17), ankle (7), heel (5) and other sites (4). The types of free flap included latissimus dorsi muscle flap (10), scapular fascial flap (6), anterolateral thigh flap (6), and other flaps (30). There were four cases of vascular complications, out of which two flaps survived after intervention. The overall survival of the flaps was 96.2% (50/52). There were 19 cases of other complications at recipient sites such as partial graft loss (8), partial flap necrosis (6) and infection (5). However, these complications were not notable and were resolved with skin grafts. CONCLUSIONS: The free flap is an effective method of lower-extremity reconstruction. Good outcomes can be achieved with complete debridement and the selection of appropriate recipient vessels and flaps according to the recipient site.

Surface characteristics and bioactivity of an anodized titanium surface.

PURPOSE: The aim of this study was to evaluate the surface properties and biological response of an anodized titanium surface by cell proliferation and alkaline phosphatase activity analysis. METHODS: Commercial pure titanium (Ti) disks were prepared. The samples were divided into an untreated machined Ti group and anodized Ti group. The anodization of cp-Ti was formed using a constant voltage of 270 V for 60 seconds. The surface properties were evaluated using scanning electron microscopy, X-ray photoelectron spectroscopy, and an image analyzing microscope. The surface roughness was evaluated by atomic force microscopy and a profilometer. The contact angle and surface energy were analyzed. Cell adhesion, cell proliferation, and alkaline phosphatase activity were evaluated using mouse MC3T3-E1 cells. RESULTS: The anodized Ti group had a more porous and thicker layer on its surface. The surface roughness of the two groups measured by the profilometer showed no significant difference (P>0.001). The anodized Ti dioxide (TiO2) surface exhibited better corrosion resistance and showed a significantly lower contact angle than the machined Ti surface (P>0.001). Although there was no significant difference in the cell viability between the two groups (P>0.001), the anodized TiO2 surface showed significantly enhanced alkaline phosphatase activity (P<0.001). CONCLUSIONS: These results suggest that the surface modification of Ti by anodic oxidation improved the osteogenic response of the osteoblast cells.

Reproducibility of facial soft tissue thicknesses for craniofacial reconstruction using cone-beam CT images.

The purpose of this study was to evaluate the reproducibility of the soft tissue (ST) thicknesses at 31 landmarks using the cone-beam computed tomography (CBCT) images obtained from 20 adult subjects. Four observers carried out ST thickness measurements using Skull Measure software, and the inter- and intra-observer error rates were evaluated. Only five of 31 landmarks showed significant differences in recorded ST thickness between the observers. When excluding inexperienced observers, only one landmark showed a significant difference between the observers. Regarding the intra-observer reproducibility, the ST thickness measurements at three landmarks showed low correlation coefficients. The results of this study indicate that CBCT images can be used to measure ST thickness with high reproducibility. However, some landmarks need to be redefined to reliably measure ST thickness on CBCT images.