MDPI Acta Medica Okayama 2227-9059 12 2 2024 Morphometric Analysis of the Eye by Magnetic Resonance Imaging in MGST2-Gene-Deficient Mice 370 EN Chaomulige Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University Toshihiko Matsuo Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University Kohei Sugimoto Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University Mary Miyaji Department of Medical Neurobiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Osamu Hosoya Department of Medical Neurobiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Masashi Ueda Department of Biofunctional Imaging Analysis, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Ryosuke Kobayashi Biosignal Genome Resource Center, Institute for Molecular and Cellular Regulation, Gunma University Takuro Horii Biosignal Genome Resource Center, Institute for Molecular and Cellular Regulation, Gunma University Izuho Hatada Biosignal Genome Resource Center, Institute for Molecular and Cellular Regulation, Gunma University Strabismus, a neuro-ophthalmological condition characterized by misalignment of the eyes, is a common ophthalmic disorder affecting both children and adults. In our previous study, we identified the microsomal glutathione S-transferase 2 (MGST2) gene as one of the potential candidates for comitant strabismus susceptibility in a Japanese population. The MGST2 gene belongs to the membrane-associated protein involved in the generation of pro-inflammatory mediators, and it is also found in the protection against oxidative stress by decreasing the reactivity of oxidized lipids. To look for the roles of the MGST2 gene in the development, eye alignment, and overall morphology of the eye as the possible background of strabismus, MGST2 gene knockout (KO) mice were generated by CRISPR/Cas9-mediated gene editing with guide RNAs targeting the MGST2 exon 2. The ocular morphology of the KO mice was analyzed through high-resolution images obtained by a magnetic resonance imaging (MRI) machine for small animals. The morphometric analyses showed that the height, width, and volume of the eyeballs in MGST2 KO homozygous mice were significantly greater than those of wild-type mice, indicating that the eyes of MGST2 KO homozygous mice were significantly enlarged. There were no significant differences in the axis length and axis angle. These morphological changes may potentially contribute to the development of a subgroup of strabismus. No potential conflict of interest relevant to this article was reported.

Springer Acta Medica Okayama 0914-7187 34 2020 Improvement of biodistribution profile of a radiogallium-labeled, αvβ6 integrin-targeting peptide probe by incorporation of negatively charged amino acids 575 582 EN Shunsuke Nakamura Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Aya Matsuno Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Masashi Ueda Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Objective Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers. Since αvβ6 integrin has been reported as a promising target for PDAC diagnosis, we previously developed H-Cys(mal-NOTA-67Ga)-(Gly)6-A20FMDV2-NH2 ([67Ga]CG6) as an αvβ6 integrin-targeting probe. Although [67Ga]CG6 specifically binds to αvβ6 integrin-positive xenografts, the uptake of [67Ga]CG6 in the organs surrounding the pancreas, such as the liver and spleen, was comparable to that in the αvβ6 integrin-positive xenografts. We hypothesized that the undesirable accumulation of [67Ga]CG6 in those organs was caused by the positive charges of [67Ga]CG6 (+ 3). In this study, we aimed to decrease [67Ga]CG6 uptake in the liver and spleen by reducing the electric charges of the probe. Methods We synthesized H-Cys(mal-NOTA-67Ga)-(Asp)6-A20FMDV2-NH2 ([67Ga]CD6) and evaluated its affinity to αvβ6 integrin via in vitro competitive binding assay. Isoelectric points of the probes were determined by electrophoresis. Biodistribution study, autoradiography, and immunostaining for β6 integrin were conducted using αvβ6 integrin-positive and negative tumor-bearing mice. Results In vitro competitive binding assay showed that the alteration of the linker had a negligible impact on the affinity of [67Ga]CG6 to αvβ6 integrin. The results of electrophoresis revealed that [67Ga]CG6 was positively charged whereas [67Ga]CD6 was negatively charged. In the biodistribution study, the uptake of [67Ga]CD6 in the αvβ6 integrin-positive xenografts was significantly higher than that in the αvβ6 integrin-negative ones at 60 and 120 min. The uptake of [67Ga]CD6 in the liver and spleen was more than two-fold lower than that of [67Ga]CG6 at both time points. In the immunohistochemistry study, the radioactivity accumulated areas in the autoradiogram of the αvβ6 integrin-positive xenograft roughly coincided with β6 integrin-expressing areas. Conclusion We have successfully reduced the nonspecific uptake in the liver and spleen by altering the linker amino acid from G6 to D6. [67Ga]CD6 overcame the drawbacks of [67Ga]CG6 in its biodistribution. No potential conflict of interest relevant to this article was reported.

Elsevier Acta Medica Okayama 0968-0896 28 1 2020 Development and characterization of a 68Ga-labeled A20FMDV2 peptide probe for the PET imaging of αvβ6 integrin-positive pancreatic ductal adenocarcinoma 115189 EN Takashi Ui Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Masashi Ueda Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Yusuke Higaki Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama Universit Shinichiro Kamino Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Kohei Sano Graduate School of Pharmaceutical Sciences, Kyoto University Hiroyuki Kimura Graduate School of Pharmaceutical Sciences, Kyoto University Hideo Saji Graduate School of Pharmaceutical Sciences, Kyoto University Shuichi Enomoto RIKEN Center for Life Science Technologies Pancreatic ductal adenocarcinoma (PDAC) is known to be one of the most lethal cancers. Since the majority of patients are diagnosed at an advanced stage, development of a detection method for PDAC at an earlier stage of disease progression is strongly desirable. Integrin αVβ6 is a promising target for early PDAC detection because its expression increases during precancerous changes. The present study aimed to develop an imaging probe for positron emission tomography (PET) which targets αVβ6 integrin-positive PDAC. We selected A20FMDV2 peptide, which binds specifically to αvβ6 integrin, as a probe scaffold, and 68Ga as a radioisotope. A20FMDV2 peptide has not been previously labeled with 68Ga. A cysteine residue was introduced to the N-terminus of the probe at a site-specific conjugation of maleimide-NOTA (mal-NOTA) chelate. Different numbers of glycine residues were also introduced between cysteine and the A20FMDV2 sequence as a spacer in order to reduce the steric hindrance of the mal-NOTA on the binding probe to αVβ6 integrin. In vitro, the competitive binding assay revealed that probes containing a 6-glycine linker ([natGa]CG6 and [natGa]Ac-CG6) showed high affinity to αVβ6 integrin. Both probes could be labeled by 67/68Ga with high radiochemical yield (>50%) and purity (>98%). On biodistribution analysis, [67Ga]Ac-CG6 showed higher tumor accumulation, faster blood clearance, and lower accumulation in the surrounding organs of pancreas than did [67Ga]CG6. The αVβ6 integrin-positive xenografts were clearly visualized by PET imaging with [68Ga]Ac-CG6. The intratumoral distribution of [68Ga]Ac-CG6 coincided with the αVβ6 integrin-positive regions detected by immunohistochemistry. Thus, [68Ga]Ac-CG6 is a useful peptide probe for the imaging of αVβ6 integrin in PDAC. No potential conflict of interest relevant to this article was reported.

Elsevier Science Acta Medica Okayama 0969-8051 43 6 2016 Noninvasive evaluation of nicotinic acetylcholine receptor availability in mouse brain using single-photon emission computed tomography with [(123)I]5IA. 372 378 EN Yuki Matsuura Department of Pharmaceutical Analytical Chemistry, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Masashi Ueda Department of Pharmaceutical Analytical Chemistry, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Yusuke Higaki Department of Pharmaceutical Analytical Chemistry, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Keiko Watanabe Department of Pharmaceutical Analytical Chemistry, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Shogo Habara Department of Pharmaceutical Analytical Chemistry, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Shinichiro Kamino Department of Pharmaceutical Analytical Chemistry, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Hideo Saji Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University Shuichi Enomoto Department of Pharmaceutical Analytical Chemistry, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University INTRODUCTION: Nicotinic acetylcholine receptors (nAChRs) are of great interest because they are implicated in higher brain functions. Nuclear medical imaging is one of the useful techniques for noninvasive evaluation of physiological and pathological function in living subjects. Recent progress in nuclear medical imaging modalities enables the clear visualization of the organs of small rodents. Thus, translational research using nuclear medical imaging in transgenic mice has become possible and helps to elucidate human disease pathology. However, imaging of α4β2 nAChRs in the mouse brain has not yet been performed. The purpose of this study was to assess the feasibility of single-photon emission computed tomography (SPECT) with 5-[(123)I]iodo-3-[2(S)-azetidinylmethoxy]pyridine ([(123)I]5IA) for evaluating α4β2 nAChR availability in the mouse brain. METHODS: A 60-min dynamic SPECT imaging session of α4β2 nAChRs in the mouse brain was performed. The regional distribution of radioactivity in the SPECT images was compared to the density of α4β2 nAChRs measured in an identical mouse. Alteration of nAChR density in the brains of Tg2576 mice was also evaluated. RESULTS: The mouse brain was clearly visualized by [(123)I]5IA-SPECT and probe accumulation was significantly inhibited by pretreatment with (-)-nicotine. The regional distribution of radioactivity in SPECT images showed a significant positive correlation with α4β2 nAChR density measured in an identical mouse brain. Moreover, [(123)I]5IA-SPECT was able to detect the up-regulation of α4β2 nAChRs in the brains of Tg2576 transgenic mice. CONCLUSIONS: [(123)I]5IA-SPECT imaging would be a promising tool for evaluating α4β2 nAChR availability in the mouse brain and may be useful in translational research focused on nAChR-related diseases. No potential conflict of interest relevant to this article was reported.

Springer Acta Medica Okayama 1536-1632 21 3 2018 Evaluation of the Relationship Between Cognitive Impairment, Glycometabolism, and Nicotinic Acetylcholine Receptor Deficits in a Mouse Model of Alzheimer's Disease 519 528 EN Yuki Matsuura Department of Biofunction Imaging Analysis, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Masashi Ueda Department of Biofunction Imaging Analysis, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Yusuke Higaki Department of Biofunction Imaging Analysis, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Kohei Sano Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University Hideo Saji Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University Shuichi Enomoto Department of Biofunction Imaging Analysis, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University PURPOSE: In patients with Alzheimer's disease (AD), the loss of cerebral nicotinic acetylcholine receptors (nAChRs) that are implicated in higher brain functions has been reported. However, it is unclear if nAChR deficits occur in association with cognitive impairments. The purpose of this study was to assess the relationship between nAChR deficits and cognitive impairments in a mouse model of AD (APP/PS2 mice). PROCEDURES: The cognitive abilities of APP/PS2 and wild-type mice (aged 2-16 months) were evaluated using the novel object recognition test. Double-tracer autoradiography analyses with 5-[125I]iodo-A-85380 ([125I]5IA: α4β2 nAChR imaging probe) and 2-deoxy-2-[18F]fluoro-D-glucose were performed in both mice of different ages. [123I]5IA-single-photon emission tomography (SPECT) imaging was also performed in both mice at 12 months of age. Furthermore, each age cohort was investigated for changes in cognitive ability and expression levels of α7 nAChRs and N-methyl-D-aspartate receptors (NMDARs). RESULTS: No significant difference was found between the APP/PS2 and wild-type mice at 2-6 months of age in terms of novel object recognition memory; subsequently, however, APP/PS2 mice showed a clear cognitive deficit at 12 months of age. [125I]5IA accumulation decreased in the brains of 12-month-old APP/PS2 mice, i.e., at the age at which cognitive impairments were first observed; this result was supported by a reduction in the protein levels of α4 nAChRs using Western blotting. nAChR deficits could be noninvasively detected by [123I]5IA-SPECT in vivo. In contrast, no significant changes in glycometabolism, expression levels of α7 nAChRs, or NMDARs were associated with cognitive impairments in APP/PS2 mice. CONCLUSION: A decrease in cerebral α4β2 nAChR density could act as a biomarker reflecting cognitive impairments associated with AD pathology. No potential conflict of interest relevant to this article was reported.

Hindawi Acta Medica Okayama 1537744X 2014 Radiolabeled probes targeting hypoxia-inducible factor-1-active tumor microenvironments 165461 EN Masashi Ueda Department of Pharmaceutical Analytical Chemistry, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Hideo Saji Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University Because tumor cells grow rapidly and randomly, hypoxic regions arise from the lack of oxygen supply in solid tumors. Hypoxic regions in tumors are known to be resistant to chemotherapy and radiotherapy. Hypoxia-inducible factor-1 (HIF-1) expressed in hypoxic regions regulates the expression of genes related to tumor growth, angiogenesis, metastasis, and therapy resistance. Thus, imaging of HIF-1-active regions in tumors is of great interest. HIF-1 activity is regulated by the expression and degradation of its α subunit (HIF-1α), which is degraded in the proteasome under normoxic conditions, but escapes degradation under hypoxic conditions, allowing it to activate transcription of HIF-1-target genes. Therefore, to image HIF-1-active regions, HIF-1-dependent reporter systems and injectable probes that are degraded in a manner similar to HIF-1α have been recently developed and used in preclinical studies. However, no probe currently used in clinical practice directly assesses HIF-1 activity. Whether the accumulation of (18)F-FDG or (18)F-FMISO can be utilized as an index of HIF-1 activity has been investigated in clinical studies. In this review, the current status of HIF-1 imaging in preclinical and clinical studies is discussed. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 16128850 12 12 2015 Histological and Nuclear Medical Comparison of Inflammation After Hemostasis with Non-Thermal Plasma and Thermal Coagulation 1338 1342 EN Masashi Ueda Graduate School of Medicine, Dentistry, and Pharmaceutica Science, Okayama University Daiki Yamagami Graduate School of Medicine, Dentistry, and Pharmaceutica Science, Okayama University Keiko Watanabe Graduate School of Medicine, Dentistry, and Pharmaceutica Science, Okayama University Asami Mori Radioisotope Research Center, Kyoto University Hiroyuki Kimura Radioisotope Research Center, Kyoto University Kohei Sano Graduate School of Pharmaceutical Sciences, Kyoto University Hideo Saji Graduate School of Pharmaceutical Sciences, Kyoto University Kenji Ishikawa Graduate School of Engineering, Nagoya University Masaru Hori Graduate School of Engineering, Nagoya University Hajime Sakakita National Institute of Advanced Industrial Science and Technology Yuzuru Ikehara National Institute of Advanced Industrial Science and Technology Shuichi Enomoto Graduate School of Medicine, Dentistry, and Pharmaceutica Science, Okayama University The objective of this study is to examine the invasiveness of hemostasis by non-thermal plasma (NTP) compared with hemostasis by thermal coagulation (TC). The inflammation recovery process after hemostasis by TC and NTP was compared by using histological methods and nuclear medical molecular imaging. The necrotic areas in the NTP group disappeared after 5 days, whereas they remained 15 days after hemostasis in the TC group. The accumulation of 2-deoxy-2-[F-18] fluoro-D-glucopyranose (F-18-FDG), which reflects the existence of inflammatory cells, was higher in the TC group than in the NTP group on day 15. Thus, this study indicates that hemostasis by NTP is less inflammatory than TC. This report is the first to evaluate inflammation that occurred after hemostasis with medical devices noninvasively. No potential conflict of interest relevant to this article was reported.