Redesign of a thioflavin-T-binding protein with a flat β-sheet to evaluate a thioflavin-T-derived photocatalyst with enhanced affinity

Amyloids, proteinous aggregates with β-sheet-rich fibrils, are involved in several neurodegenerative diseases such as Alzheimer's disease; thus, their detection is critically important. The most common fluorescent dye for amyloid detection is thioflavin-T (ThT), which shows on/off fluorescence upon amyloid binding. We previously reported that an engineered globular protein with a flat β-sheet, peptide self-assembly mimic (PSAM), can be used as an amyloid binding model. In this study, we further explored the residue-specific properties of ThT-binding to the flat β-sheet by introducing systematic mutations. We found that site-specific mutations at the ThT-binding channel enhanced affinity. We also evaluated the binding of a ThT-based photocatalyst, which showed the photooxygenation activity on the amyloid fibril upon light radiation. Upon binding of the photocatalyst to the PSAM variant, singlet oxygen-generating activity was observed. The results of this study expand our understanding of the detailed binding mechanism of amyloid-specific molecules.

Synthesis and Structural Revision of the Cyclic Hexapeptide Dimers Antatollamides A and B

The synthesis and structural revision of the dimerized cyclic hexapeptides antatollamides A (1) and B (2) are reported. These are unique peptides with two proline residues and bicyclic peptides combined by a disulfide bond. Cyclization and disulfide bond formation of the linear peptide led to antatollamide A (1). However, the 1H and 13C NMR spectra of synthetic antatollamide A (1) were not consistent with those of isolated antatollamide A (1). Meanwhile, the NMR spectra of the monomeric cyclic hexapeptide cyclo(Pro-Pro-Phe-dCys-Ile-Val) (3) and the isolated antatollamide A (1) were identified completely. In addition, we found that isolated antatollamide B (2) is cyclo(Pro-Pro-dPhe-dCys-Ile-Val) (4).

Development of 1,5-diarylpyrazoles as EGFR/JNK-2 dual inhibitors: design, synthesis, moleecular docking, and bioactivity evaluation

The eradication of multifactorial diseases, such as cancer, requires the design of drug candidates that attack multiple targets that contribute to the progression and proliferation of such diseases. Here, 1,5-diarylpyrazole derivatives bearing vanillin or sulfanilamide are developed as potential dual inhibitors of epidermal growth factor receptor (EGFR)/c-Jun N-terminal kinase 2 (JNK-2) for possible anticancer activity. These derivatives inhibited the growths of DLD-1, HeLa, K-562, SUIT-2 and HepG2 cancer cell lines, with minimum concentration required to inhibit half of the cellular growth (IC50) values of 2.7-63 μM. The tests confirmed that 5b and 5d were potent JNK-2 inhibitors, with IC50 of 2.0 and 0.9 μM, respectively, whereas 6 h selectively inhibited EGFR protein kinase (EGFR-PK) (IC50 = 1.7 μM). Notably, 6c inhibited both kinases, with IC50 values of 2.7 and 3.0 μM against EGFR-PK and JNK-2, respectively, offering a reference for designing mutual inhibitors of EGFR/JNK-2. The docking studies revealed the ability of the pyrazole ring to bind to the hinge region of the ATP binding site, thereby supporting the experimental inhibitory results. Furthermore, the developed compounds could induce apoptosis and induce cell cycle arrest at different cell phases.

α-1,3-Glucanase from the gram-negative bacterium Flavobacterium sp. EK-14 hydrolyzes fungal cell wall α-1,3-glucan

The glycoside hydrolase (GH) 87 α-1,3-glucanase (Agl-EK14) gene was cloned from the genomic DNA of the gram-negative bacterium Flavobacterium sp. EK14. The gene consisted of 2940 nucleotides and encoded 980 amino acid residues. The deduced amino acid sequence of Agl-EK14 included a signal peptide, a catalytic domain, a first immunoglobulin-like domain, a second immunoglobulin-like domain, a ricin B-like lectin domain, and a carboxyl-terminal domain (CTD) involved in extracellular secretion. Phylogenetic analysis of the catalytic domain of GH87 enzymes suggested that Agl-EK14 is distinct from known clusters, such as clusters composed of α-1,3-glucanases from bacilli and mycodextranases from actinomycetes. Agl-EK14 without the signal peptide and CTD hydrolyzed α-1,3-glucan, and the reaction residues from 1 and 2% substrates were almost negligible after 1440 min reaction. Agl-EK14 hydrolyzed the cell wall preparation of Aspergillus oryzae and released glucose, nigerose, and nigero-triose from the cell wall preparation. After treatment of A. oryzae live mycelia with Agl-EK14 (at least 0.5 nmol/ml), mycelia were no longer stained by red fluorescent protein-fused α-1,3-glucan binding domains of α-1,3-glucanase Agl-KA from Bacillus circulans KA-304. Results suggested that Agl-EK14 can be applied to a fungal cell wall lytic enzyme.

Heterologous expression of α-1,3-glucanase Agn1p from Schizosaccharomyces pombe, and efficient production of nigero-oligosaccharides by enzymatic hydrolysis from solubilized α-1,3;1,6-glucan

The glycoside hydrolase family 71 α-1,3-glucanase (Agn1p) of Schizosaccharomyces pombe was expressed in Escherichia coli Rosetta-gami B (DE3). Agn1p (0.5 nmol/mL) hydrolyzed insoluble α-1,3-glucan (1%), and about 3.3 mm reducing sugars were released after 1440 min of reaction. The analysis of reaction products by high-performance liquid chromatography revealed that pentasaccharides accumulated in the reaction mixture as the main products, along with a small amount of mono-, di-, tri-, tetra-, and hexasaccharides. Soluble glucan was prepared from insoluble α-1,3;1,6-glucan by alkaline and sonication treatment to improve the hydrolytic efficiency. As a result, this solubilized α-1,3;1,6-glucan maintained a solubilized state for at least 6 h. Agn1p (0.5 nmol/mL) hydrolyzed the solubilized α-1,3;1,6-glucan (1%), and about 8.2 mm reducing sugars were released after 240 min of reaction. Moreover, Agn1p released about 12.3 mm reducing sugars from 2% of the solubilized α-1,3;1,6-glucan.

Development and Assessment of 1,5-Diarylpyrazole/Oxime Hybrids Targeting EGFR and JNK-2 as Antiproliferative Agents: A Comprehensive Study through Synthesis, Molecular Docking, and Evaluation

New 1,5-diarylpyrazole oxime hybrid derivatives (scaffolds A and B) were designed, synthesized, and then their purity was verified using a variety of spectroscopic methods. A panel of five cancer cell lines known to express EGFR and JNK-2, including human colorectal adenocarcinoma cell line DLD-1, human cervical cancer cell line Hela, human leukemia cell line K562, human pancreatic cell line SUIT-2, and human hepatocellular carcinoma cell line HepG2, were used to biologically evaluate for their in vitro cytotoxicity for all the synthesized compounds 7a-j, 8a-j, 9a-c, and 10a-c. The oxime containing compounds 8a-j and 10a-c were more active as antiproliferative agents than their non-oxime congeners 7a-j and 9a-c. Compounds 8d, 8g, 8i, and 10c inhibited EGFR with IC50 values ranging from 8 to 21 µM when compared with sorafenib. Compound 8i inhibited JNK-2 as effectively as sorafenib, with an IC50 of 1.0 µM. Furthermore, compound 8g showed cell cycle arrest at the G2/M phase in the cell cycle analysis of the Hela cell line, whereas compound 8i showed combined S phase and G2 phase arrest. According to docking studies, oxime hybrid compounds 8d, 8g, 8i, and 10c exhibited binding free energies ranging from -12.98 to 32.30 kcal/mol at the EGFR binding site whereas compounds 8d and 8i had binding free energies ranging from -9.16 to -12.00 kcal/mol at the JNK-2 binding site.

Nigero-oligosaccharide production by enzymatic hydrolysis from alkaline-pretreated α-1,3-glucan

Nigero-oligosaccharides are α-1,3-linked oligomers of glucose. Glycoside hydrolase 87 type α-1,3-glucanase Agl-KA from Bacillus circulans KA304 is an endo-lytic enzyme that releases nigero-oligosaccharides (tetra-, tri-, and di-saccharide) from α-1,3-glucan. α-1,3-Glucan is insoluble under natural conditions, thus the efficiency of enzymatic hydrolysis is low and only 5 mM of reducing sugars were released from 1% glucan by Agl-KA. To improve hydrolytic efficiency, α-1,3-glucan was solubilized by 1 M NaOH and alkaline-solubilized glucan was adjusted to approximately pH 8. As a result, glucan maintained a solubilized state. This alkaline-pretreated α-1,3-glucan (1%) was hydrolyzed by Agl-KA (0.64 nmol/mL) and approximately 11.6 mM of reducing sugars were released at 240 min of reaction. When 0.016, 0.032, and 0.13 nmol/mL enzyme were added, reducing sugar reached approximately 5.1, 7.5, and 9.8 mM, respectively, and reaction mixtures containing 0.016 and 0.032 nmol/mL enzyme gradually became cloudy. Our findings suggest α-1,3-glucan cannot maintain its solubilized state and gradually becomes insoluble. For deletion enzyme of α-1,3-glucan binding domains from Agl-KA (AglΔDCD-UCD) on glucan hydrolysis (2%), reducing sugar concentrations released by AglΔDCD-UCD were almost the same as Agl-KA. These findings suggest that alkaline-pretreated α-1,3-glucan maintains a soluble state during a short time period and that glucan is efficiently hydrolyzed even by α-1,3-glucanase without α-1,3-glucan binding domains.

Structure-Activity Relationship Study of N-Hydroxyphtalimide Derivatives for the Detection of Amines during Fmoc-Solid-Phase Peptide Synthesis

Previously, we developed a method for the detection of unprotected amino groups based on their reversible reaction with N-hydroxyphthalimide (NHPI) to form intensely colored products, which can be useful when conducting solid-phase peptide synthesis. Here, we describe a structure-activity relationship study of NHPI derivatives to identify the derivative best suited for this method using a spectrophotometer toward the estimation of chemical yields. We found that the products resulting from the reaction of the derivative with an unprotected amino group were only intensely colored if the structure of the derivative incorporated an NHPI framework. We also prepared five peptides, including those containing N-methyl and D-amino acid, and Pro residues, using our reversible detection method to detect unprotected amino groups. The mechanism of the detection reaction was also studied by the structural analysis of the NHPI (1) and diisopropylamine complex and concluded to entail salt formation between the N-hydroxy group and amine.

Early enteral nutrition with arginine compensates for negative nitrogen balance in patients undergoing curative total gastrectomy

The effects of early enteral arginine-rich nutrition (EAN) were analyzed among patients undergoing curative-intent total gastrectomy for gastric cancer. There were 19 patients in this prospective study, all randomly assigned to either a parenteral nutrition (PN) group or an EAN group for the first seven days after surgery. The EAN group received 1.8-fold greater arginine (10.1 g/day) compared with the PN group, which was administered through an enteral tube inserted into the jejunal loop. Both groups were provided almost identical amounts of total amino acids (54 g/day), and the total energy was set at 65% of the total requirement (25 kcal/kg/day). No significant differences were observed between the two groups in postoperative complications, length of hospital stay, oral intake, nutritional status, or body weight. The serum arginine profile was similar in the two groups, as it decreased significantly on postoperative day (POD) 1, and gradually returned to preoperative levels by POD 7. The nitrogen balance remained negative until POD 7 in the PN group, but turned neutral at POD 7 in the EAN group. While we could not confirm body weight loss improvement, these results suggested that early arginine-rich enteral nutrition could improve the nitrogen balance after total gastrectomy. J. Med. Invest. 70 : 325-333, August, 2023.

Comprehensive evaluation of three-dimensional anatomy of perigastric vessels using enhanced multidetector-row computed tomography

BACKGROUND

To perform laparoscopic gastrectomy safely, we aimed to comprehensively re-evaluate perigastric vessel anatomies using a three-dimensional angiography reconstructed from enhanced multidetector-row computed tomography data.

METHODS

Perigastric vessel anatomy was preoperatively analyzed using a multidetector-row computed tomography-based three-dimensional angiography reconstructed in 127 patients undergoing gastric surgery.

RESULTS

Of the 67 left gastric veins that ran along the dorsal side of the arteries, 59 (88.1%) ran along the dorsal side of the common hepatic artery and flowed into the portal vein. In 18 cases, a common trunk of one to three left gastric arteries and the replaced left hepatic artery was observed. The left inferior phrenic artery ramified from the left gastric artery in 5.5% of the cases. The right gastric artery was classified into distal (73.2%), caudal (18.1%), and proximal (8.7%) types. The infra-pyloric artery was also classified into distal (64.6%), caudal (26.0%), and proximal (9.4%) types. The posterior gastric artery branched as a common trunk with the superior polar artery in the proximal (37.9%) and distal (18.4%) regions of the splenic artery. The left gastroepiploic artery ramified from the splenic (18.1%) and inferior terminal arteries (81.9%). No, one, and two gastric branches of the left gastroepiploic artery, which ramified between the roots of the left gastroepiploic artery and its omental branch, were found in 36.5%, 49.2%, and 14.3% of the cases, respectively.

CONCLUSIONS

Preoperative 3D angiography is useful for the precise evaluation of perigastric vessel anatomies, and may help us to perform laparoscopic gastrectomy and robotic surgery safely.

Artificial intelligence-based classification of peripheral blood nucleated cells using label-free imaging flow cytometry

Label-free image identification of circulating rare cells, such as circulating tumor cells within peripheral blood nucleated cells (PBNCs), the vast majority of which are white blood cells (WBCs), remains challenging. We previously described developing label-free image cytometry for classifying live cells using computer vision technology for pattern recognition, based on the subcellular structure of the quantitative phase microscopy images. We applied our image recognition methods to cells flowing in a flow cytometer microfluidic channel, and differentiated WBCs from cancer cell lines (area under receiver operating characteristic curve = 0.957). We then applied this method to healthy volunteers' and advanced cancer patients' blood samples and found that the non-WBC fraction rates (NWBC-FRs), defined as the percentage of cells classified as non-WBCs of the total PBNCs, were significantly higher in cancer patients than in healthy volunteers. Furthermore, we monitored NWBC-FRs over the therapeutic courses in cancer patients, which revealed the potential ability in monitoring the clinical status during therapy. Our image recognition system has the potential to provide a morphological diagnostic tool for circulating rare cells as non-WBC fractions.

Synthesis and Configuration Confirmation of the ATHOD Fatty Amino Acid Residue in the Burkholdines

Eight possible diastereomers of the 3-amino-5,6,7-trihydroxy octadecanoic acid (ATHOD) moiety of the burkholdines (Bks) have been synthesized and their configurations assigned. Though the relative configuration of the triol in the ATHOD residue of the Bks was proposed to be anti-anti-anti in the literature, ¹H NMR spectra of our synthesized anti-anti-anti ATHOD derivative was inconsistent with that of the isolated ATHOD residue, suggesting that the assignment of the relative configuration of that residue in the literature was incorrect. However, by comparison of the NMR data of our ATHOD derivatives with that of configurationally defined samples of 2-amino-4-pentanol using Kishi's NMR database method, we conclude that the absolute configuration of the ATHOD moiety is (3R,5S,6R,7S). In addition, we revealed that the ATHOD residue present in the occidiofungins A-D has the same configuration as that in all the Bks.

Saturated Fatty Acids in Cell Membrane Lipids Induce Resistance to 5-Fluorouracil in Colorectal Cancer Cells

BACKGROUND/AIM

Resistance to chemotherapy is a major obstacle for patients with unresectable colorectal cancer (CRC); however, the factors that induce chemoresistance have not been elucidated. Lipid composition influences neoplastic behaviour. Therefore, this study examined whether lipid composition affects sensitivity to chemotherapeutic agents in CRC.

MATERIALS AND METHODS

We performed a lipidomic analysis of a CRC xenograft-derived spheroid model to identify potential relationships between the lipid profile and chemoresistance to 5-fluorouracil (5-FU). Genetic and pharmacological modulation of lipid synthesis were also used in the HCT-116 and DLD-1 CRC cell lines to further characterize resistance to 5-FU.

RESULTS

Our lipidomic profiling revealed that phospholipids with saturated fatty acids (SFAs) were more abundant in 5-FU-resistant spheroids. The importance of phospholipids containing SFA in chemoresistance was confirmed by showing that in HCT-116 and DLD-1 cells, genetic or pharmacological inactivation of stearoyl-CoA desaturase-1, a key enzyme that converts SFAs to monounsaturated fatty acids, increased the proportion of SFAs in membranous phospholipids and reduced cell membrane fluidity, and this ultimately resulted in resistance to 5-FU.

CONCLUSION

These data suggest that the saturated to monounsaturated fatty acid ratio in cellular membranous phospholipids affects sensitivity to chemotherapeutic agents.

Construction of a fusion protein consisting of α-1,3-glucan-binding domains and tetrameric red fluorescent protein, which is involved in the aggregation of α-1,3-glucan and inhibition of fungal biofilm formation

Agl-KA, an α-1,3-glucan-hydrolyzing enzyme from Bacillus circulans KA-304, has three α-1,3-glucan-binding domains DS1, CB6, and DS2 (DCD). While their individual binding activities toward insoluble α-1,3-glucan and fungal cell-wall are weak, the three domains in combination bind strongly to the α-1,3-glucan and the cell-wall. In this study, we constructed DCD-tetraRFP by fusing DCD with DsRed-Express2, a tetrameric red fluorescent protein. DCD-tetraRFP forms a tetramer in an aqueous solution and contains twelve substrate-binding domains in one complex. We also constructed DCD-monoGFP by fusing DCD with AcGFP1, a monomeric green fluorescent protein. The molecular weight of DCD-tetraRFP and DCD-monoGFP were compared. The results of gel filtration chromatography and dynamic light scattering indicated that DCD-tetraRFP was larger than DCD-monoGFP, suggesting that DCD-tetraRFP had a tetrameric structure. In addition, DCD-tetraRFP bound to insoluble α-1,3-glucan strongly, and the amount of DCD-tetraRFP binding to 0.01% α-1,3-glucan was about twice of DCD-monoGFP. The Kd values of DCD-tetraRFP (measurements per subunit) and DCD-monoGFP were 0.16 and 0.84 μM, respectively. Adding DCD-tetraRFP to a suspension of α-1,3-glucan caused glucan aggregation; however, adding DCD-monoGFP did not. These data suggested that DCD-tetraRFP had four DCDs sterically arranged in different directions so that DCD-tetraRFP cross-linked with the substrate, causing aggregation. Lastly, the aggregates of DCD-tetraRFP and α-1,3-glucan captured Aspergillus oryzae conidia and decreased their biofilm formation by 80% in a 24-well dish.

GH-16 type β-1,3-glucanase from <i>Lysobacter</i> sp. MK9-1 enhances antifungal activity of GH-19 type chitinase, and its glucan-binding domain binds to fungal cell-wall

The GH-16 type β-1,3-glucanase (BgluC16MK) gene of Lysobacter sp. MK9-1 was cloned to study its antifungal activities. BgluC16MK displays amino acid sequence similarity with GluC from L. enzymogenes strain N4-7. BgluC16MK includes a signal sequence, a catalytic domain and carbohydrate-binding module family 6-type β-glucan binding domain (B-GBD). The expression of the BgluC16MK gene in Escherichia coli without the signal sequence resulted in antifungal activity at a dose of 0.6-0.8 nmol/disk. However, BgluC16MK displayed antifungal activity at a dose of 0.025 nmol/disk in combination with Chi19MK. Substrate-specific assay revealed that purified BgluC16MK hydrolyzed insoluble curdlan more readily than the soluble substrate. Furthermore, to explore the binding selectivity of B-GBD of BgluC16MK, we constructed a fusion protein (B-GBD-GFP) using the B-GBD and green fluorescent protein. The activity of the fusion protein against various substrates indicates that B-GBD was selective for glucans with β-1,3-linkages. An additional study demonstrated the binding ability of B-GBD-GFP to the cell-wall of living fungi, such as T. reesei and Aspergillus oryzae. These findings suggest that BgluC16MK can be utilized to generate antifungal enzyme preparations and that the fusion protein B-GBD-GFP can be used to identify the fungal cell surface structure using β-glucans.

Tailor-Made Amino Acids in Pharmaceutical Industry: Synthetic Approaches to Aza-Tryptophan Derivatives

Over the recent years there has been a noticeable upsurge of interest in aza-analogs of tryptophan which are isosteric to the latter and found numerous applications in medicinal, bioorganic chemistry, and peptide research. In the present review article, five aza-tryptophan derivatives are profiled, including aza-substitution in the positions 2, on the five-membered ring, as well as in positions 4, 5, 6, and 7 on the six-membered ring. A detailed and comprehensive literature overview of the synthetic methods for the preparation of these aza-tryptophans is presented and general facets of the biological properties and most promising applications are discussed.

Molecular hybrids: A five-year survey on structures of multiple targeted hybrids of protein kinase inhibitors for cancer therapy

Protein kinases have grown over the past few years as a crucial target for different cancer types. With the multifactorial nature of cancer, and the fast development of drug resistance for conventional chemotherapeutics, a strategy for designing multi-target agents was suggested to potentially increase drug efficacy, minimize side effects and retain the proper pharmacokinetic properties. Kinase inhibitors were used extensively in such strategy. Different kinase inhibitor agents which target EGFR, VEGFR, c-Met, CDK, PDK and other targets were merged into hybrids with conventional chemotherapeutics such as tubulin polymerization and topoisomerase inhibitors. Other hybrids were designed gathering kinase inhibitors with targeted cancer therapy such as HDAC, PARP, HSP 90 inhibitors. Nitric oxide donor molecules were also merged with kinase inhibitors for cancer therapy. The current review presents the hybrids designed in the past five years discussing their design principles, results and highlights their future perspectives.

Design, synthesis, and evaluation of the self-assembled antimicrobial peptides based on the ovalbumin-derived peptide TK913

The preparation, self-assembly, and antimicrobial activity of peptides based on TK913 is described. TK9Z4 incorporating a Pro-Pro motif exhibited self-assembly but no cytotoxicity. However, peptide TKZ3 (obtained by changing the amino acid sequence of TK9Z4) showed morphological changes at different concentrations, potent antimicrobial activity, low cytotoxicity, and trypsin resistance. Accordingly, TKZ3 is proposed as new AMP derived from ovalbumin-derived peptides.

New pharmaceuticals approved by FDA in 2020: Small-molecule drugs derived from amino acids and related compounds

Amino acids (AAs) play an important role in the modern health industry as key synthetic precursors for pharmaceuticals, biomaterials, biosensors, and drug delivery systems. Currently, over 30% of small-molecule drugs contain residues of tailor-made AAs or derived from them amino-alcohols and di-amines. In this review article, we profile 12 AA-derived new pharmaceuticals approved by the FDA in 2020. These newly introduced drugs include Tazverik (epithelioid sarcoma), Gemtesa (overactive bladder), Zeposia (multiple sclerosis), Byfavo (induction and maintenance of procedural sedation), Cu 64 dotatate, and Gallium 68 PSMA-11 (both PET imaging), Rimegepant (acute migraine), Zepzelca (lung cancer), Remdesivir (COVID-19), Amisulpride (nausea and vomiting), Setmelanotide (obesity), and Lonafarnib (progeria syndrome). For each compound, we describe the spectrum of biological activity, medicinal chemistry discovery, and synthetic preparation.

Carnosine dipeptidase II (CNDP2) protects cells under cysteine insufficiency by hydrolyzing glutathione-related peptides

The knockout (KO) of the cystine transporter xCT causes ferroptosis, a type of iron-dependent necrotic cell death, in mouse embryonic fibroblasts, but this does not occur in macrophages. In this study, we explored the gene that supports cell survival under a xCT deficiency using a proteomics approach. Analysis of macrophage-derived peptides that were tagged with iTRAQ by liquid chromatography-mass spectrometry revealed a robust elevation in the levels of carnosine dipeptidase II (CNDP2) in xCT KO macrophages. The elevation in the CNDP2 protein levels was confirmed by immunoblot analyses and this elevation was accompanied by an increase in hydrolytic activity towards cysteinylglycine, the intermediate degradation product of glutathione after the removal of the γ-glutamyl group, in xCT KO macrophages. Supplementation of the cystine-free media of Hepa1-6 cells with glutathione or cysteinylglycine extended their survival, whereas the inclusion of bestatin, an inhibitor of CNDP2, counteracted the effects of these compounds. We established CNDP2 KO mice by means of the CRISPR/Cas9 system and found a decrease in dipeptidase activity in the liver, kidney, and brain. An acetaminophen overdose (350 mg/kg) showed not only aggravated hepatic damage but also renal injury in the CNDP2 KO mice, which was not evident in the wild-type mice that were receiving the same dose. The aggravated renal damage in the CNDP2 KO mice was consistent with the presence of abundant levels of CNDP2 in the kidney, the organ prone to developing ferroptosis. These collective data imply that cytosolic CNDP2, in conjugation with the removal of the γ-glutamyl group, recruits Cys from extracellular GSH and supports redox homeostasis of cells, particularly in epithelial cells of proximal tubules that are continuously exposed to oxidative insult from metabolic wastes that are produced in the body.

Surgical outcomes in gastroenterological surgery in Japan: Report of the National Clinical Database 2011-2019

BACKGROUND

We aimed to present the 2019 annual report of the gastroenterological section of the National Clinical Database (NCD).

METHODS

We reviewed 609,589 cases recorded in 2019 and 5,029,764 cases registered from 2011 to 2019 for the 115 selected gastroenterological surgical procedures.

RESULTS

The main features of gastroenterological surgery in Japan were similar to those described in the 2018 annual report, namely, that 1) operative numbers gradually increased in all procedures, except gastrectomy and hepatectomy, which decreased in these years; 2) in all eight major gastroenterological surgeries, the age distribution tended toward older patients; 3) the morbidity of esophagectomy, hepatectomy, and pancreaticoduodenectomy increased, but mortality was minimized in all procedures; 4) all eight major gastroenterological procedures have increasingly been performed under laparoscopy; and 5) board-certified surgeons were increasingly involved. These trends in recent years were more prominent in 2019.

CONCLUSIONS

Thanks to the continuous cooperation and dedication of the surgeons, medical staff, and surgical clinical reviewers who registered the clinical data into the NCD, it is possible to understand the comprehensive landscape of surgery in Japan and to disclose new evidence in this field. The Japanese Society of Gastroenterological Surgery will continue to promote the value of this database and encourage the use of feedback and clinical studies using the NCD, now and in the future. Generating further approaches to surgical quality improvement are important directions for future research.

Significance of the Glasgow prognostic score for short-term surgical outcomes: A nationwide survey using the Japanese National Clinical Database

AIM

Preoperative inflammation-based Glasgow prognostic score (GPS) is a useful tool for predicting long-term prognosis in cancer patients. However, its association with postoperative short-term outcomes remains unknown. The aim of this study is to investigate the association between GPS and postoperative morbidity and mortality among patients undergoing surgery for various gastrointestinal malignancies.

METHODS

Using the Japanese National Clinical Database, we analyzed the records of 312 357 patients with gastrointestinal malignancy who underwent six typical elective surgeries, including esophagectomy, distal gastrectomy, total gastrectomy, right hemicolectomy, low anterior resection, and pancreaticoduodenectomy, between January 2015 and December 2018. We assigned GPS of 0, 1, or 2 to patients with no, one, or both decreased albumin and elevated C-reactive protein levels, respectively. We investigated the relationship of GPS with operative morbidity and mortality for each procedure with adjustments for patients' demographics, preoperative status, comorbidities, and cancer stages.

RESULTS

Crude operative morbidity was significantly higher for GPS 1 and 2 than GPS 0 patients in all procedures except pancreaticoduodenectomy. The postoperative length of hospital stay was significantly longer for GPS 1 and 2 patients in all procedures (P < .001). Operative mortality was also higher for GPS 1 and 2 patients in all procedures. The associations remained significant after adjustments for potential confounders of age, sex, physical status, tumor classification, use of preoperative therapy, and comorbidities.

CONCLUSION

This nationwide study provides solid evidence on the strong association between GPS and postoperative outcomes.

Comparative study of different chiral ligands for dynamic kinetic resolution of amino acids

Dynamic kinetic resolution (DKR) of unprotected amino acids (AAs), via intermediate formation of Ni(II) complexes, is currently a leading methodology for preparation of natural and tailor-made AAs in enantiomerically pure form. In this work, we conduct a comparative case study of synthetic performance of four different ligands in DKR of six AAs representing aryl-, benzyl-, alkyl-, and long alkyl-type derivatives. The results of this study allow for rational selection of ligand/AA type to develop a practical procedure for preparation of target enantiomerically pure AAs.

Nitric oxide protects against ferroptosis by aborting the lipid peroxidation chain reaction

Ferroptosis is a type of iron-dependent necrotic cell death, which is typically triggered by the depletion of intracellular glutathione (GSH), which is associated with increased lipid peroxidation. Nitric oxide (NO) is a highly reactive gaseous radical mediator with anti-oxidation properties that terminates lipid peroxidation reactions. In the current study, we report the anti-ferroptotic action of NOC18, an NO donor that spontaneously releases NO, in cells under various ferroptotic conditions in vitro. Our results indicate that, when mouse hepatoma Hepa 1-6 cells are incubated with NOC18, cell death induced by various ferroptotic stimuli such as cysteine (Cys) starvation, the inhibition of glutathione peroxidase 4 (GPX4) and treatment with tertiary-butyl hydroperoxide (TBHP) is significantly reduced. Treatment with NOC18 failed to improve the decrease in the levels of Cys or GSH and the accumulation of ferrous iron upon ferroptotic stimuli. The fluorescent intensity of C11-BODIPY^581/591, a probe that is used to detect lipid peroxidation products, was increased somewhat by treatment with NOC18 under conditions of Cys starvation, and the accumulation of lipid peroxidation end-products, as evidenced by the levels of 4-hydroxynonenal, were effectively suppressed. The pre-incubation of TBHP with NOC7, a short-lived NO donor completely eliminated its ability to trigger ferroptosis. These collective results indicate that NO exerts a cytoprotective action against various ferroptotic stimuli by aborting the lipid peroxidation chain reaction.

Profiles of institutional departments affect operative outcomes of eight gastroenterological procedures

AIM

We evaluated the association of profiles of institutional departments with operative outcomes of eight major gastroenterological procedures.

METHODS

We administered a 15-item online survey to 2634 institutional departments in 2016 to investigate the association of questionnaire responses with operative mortality for the procedures. The proportions of conditions met were listed according to institutional volume and classified according to annual operative cases in 1464 departments. Group A included departments with annual performance of <40 cases of the eight procedures, B 40-79 cases, C 80-199 cases, D 200-499 cases, and E ≥ 500 cases. We evaluated the number of conditions met for 10 of 15 items that could be improved by efforts of institutional departments, to assess whether the profiles of institutional departments had impacts on operative mortality. We built a multivariable logistic regression model for operative mortality with facilities categorized based on the number of conditions met and procedure-specific predicted mortality as explanatory variables using generalized estimating equation to account for facility-level clustering. We also examined how operative outcomes differed between facilities meeting nine or more conditions and those that did not.

RESULTS

We recognized meeting nine out of the 10 conditions as being a good indicator for having appropriate structural and process measures for gastroenterological surgery. The facilities meeting nine or more of the conditions had better operative mortality for all eight procedures.

CONCLUSIONS

Our findings reveal that the profiles of institutional departments can reflect the outcomes of gastroenterological surgery in Japan.

Validation of data quality in a nationwide gastroenterological surgical database: The National Clinical Database site-visit and remote audits, 2016-2018

BACKGROUND AND AIM

In 2015, the Japanese Society of Gastroenterological Surgery (JSGS) initiated data verification in the gastroenterological section of the National Clinical Database (NCD) and reported high accuracy of data entry. Remote audits were introduced for data validation on a trial basis in 2016 and formally accepted into use in 2017-2018. The aim of this study was to audit the data quality of the NCD gastroenterological section for 2016-2018 and to confirm the high accuracy of data in remote audits.

METHODS

Each year, 45-46 hospitals were selected for audit. Twenty cases were randomly selected in each hospital, and the accuracy of patient demographic and surgical outcome data (46 items) was compared with the corresponding medical records obtained by visiting the hospital (site-visit audit) or by mailing data from the hospital to the JSGS office (remote audit).

RESULTS

A total of 136 hospitals were included, of which 88 (64.7%) had a remote audit, and 124 936 items were evaluated with an overall data accuracy of 98.1%. There was no significant difference in terms of data accuracy between site-visit audit and remote audit. Accuracy, sensitivity, and specificity of mortality were 99.7%, 89.7%, 100% for site-visit audits and 99.8%, 97.3%, 100% for remote audits, respectively. Mean time spent on data verification per case of remote audits was shorter than that of site-visit audits (10.0 minutes vs 13.7 minutes, P < 0.001).

CONCLUSION

The audits showed that NCD data are reliable and characterized by high accuracy. Remote audits may substitute site-visit audits.

Tailor-made amino acids in the design of small-molecule blockbuster drugs

The role of amino acids (AAs) in modern health industry is well-appreciated. Residues of individual AAs, or their chemical modifications, such as diamines and amino alcohols, are frequently found in the structures of modern pharmaceuticals. The goal of this review article, is to emphasize that, currently, tailor-made AAs serve as key structural features in many most successful pharmaceuticals, so-called blockbuster drugs. In the present article, we profile 14 small-molecule drugs, underscoring the breadth of structural variety of AAs applications in numerous therapeutic areas. For each compound, we provide spectrum of biological activity, medicinal chemistry discovery, and synthetic approaches.

Maltotriose-Chlorin e6 Conjugate Linked via Tetraethyleneglycol as an Advanced Photosensitizer for Photodynamic Therapy. Synthesis and Antitumor Activities against Canine and Mouse Mammary Carcinoma Cells

Glycoconjugated chlorins represent a promising class of compounds that meet the requirements for the third-generation photosensitizer (PS) for photodynamic therapy (PDT). We have focused on the use of glucose (Glc) to improve the performance of the PS based on the Warburg effect-a phenomenon where tumors consume higher Glc levels than normal cells. However, as a matter of fact, Glc-conjugation has a poor efficacy in hydrophilic modification; thus, the resultant PS is not suitable for intravenous injection. In this study, a Glc-based oligosaccharide, such as maltotriose (Mal₃), is conjugated to chlorin e6 (Ce6). The conjugation is assisted by two additional molecular tools, such as propargyl amine and a tetraethylene glycol (TEG) derivative. This route produced the target Mal₃-Ce6 conjugate linked via the TEG spacer (Mal₃-TEG-Ce6), which shows the required photoabsorption properties in the physiological media. The PDT test using canine mammary carcinoma (SNP) cells suggested that the antitumor activity of Mal₃-TEG-Ce6 is extremely high. Furthermore, in vitro tests against mouse mammary carcinoma (EMT6) cells have been demonstrated, providing insights into the photocytotoxicity, subcellular localization, and analysis of cell death and reactive oxygen species (ROS) generation for the PDT system with Mal₃-TEG-Ce6. Both apoptosis and necrosis of the EMT6 cells occur by ROS that is generated via the photochemical reaction between Mal₃-TEG-Ce6 and molecular oxygen. Consequently, Mal₃-TEG-Ce6 is shown to be a PS showing the currently desired properties.

Association of surgeon and hospital volume with postoperative mortality after total gastrectomy for gastric cancer: data from 71,307 Japanese patients collected from a nationwide web-based data entry system

BACKGROUND

Despite interest in surgeon and hospital volume effects on total gastrectomy (TG), clinical significance has not been confirmed in a large-scale population. This study aimed at clarifying the association of surgeon and hospital volume on postoperative mortality after TG for gastric cancer among Japanese patients in National Clinical Database (NCD).

METHODS

Between 2011 and 2015, we retrospectively extracted data on TG for gastric cancer from the NCD. The primary outcome was operative mortality. We divided surgeon volume as the number of TGs performed by a patient's surgeon in the previous year: S1 (0-2 cases), S2 (3-9), S3 (10-25), S4 (26-79) and hospital volume by the number of TGs performed in the previous year: H1 (0-11 cases), H2 (12-26), H3 (27-146). We calculated the 95% confidence interval (CI) for the mortality rate based on odds ratios (OR) estimated from a hierarchical logistic regression model.

RESULTS

We analyzed 71,307 patients at 2051 institutions. Low-volume surgeons and hospitals had significantly older and poorer-risk patients with various comorbidities. The operative mortality rate decreased with surgeon volume, 2.5% in S1 and 0.6% in S4. The operative mortality was 3.1% in H1, 1.7% in H2, and 1.2% in H3. After risk adjustment for surgeon, hospital volume and patient characteristics, hospital volume was significantly associated with operative morality (H3: OR = 0.53, 95% CI 0.43-0.63).

CONCLUSIONS

We demonstrate hospital volume has an impact on postoperative mortality after TG in a nationwide population study. These findings suggest centralization may improve outcomes after TG.

The total synthesis of berberine and selected analogues, and their evaluation as amyloid beta aggregation inhibitors

The total synthesis of berberine and selected analogues. And their evaluation as amyloid β (Aβ) aggregation inhibitors is described. The key step in the synthesis, the assembly of the berberine framework, was accomplished using an intermolecular Heck reaction. Berberine analog 17 incorporating a tertiary amine moiety showed good anti Aβ aggregation activity, water solubility, and almost no toxicity to nerve cells.

Preoperative risk factors for postoperative intra-abdominal infectious complication after gastrectomy for gastric cancer using a Japanese web-based nationwide database

BACKGROUND

Postoperative intra-abdominal infectious complication (PIIC) after gastrectomy for gastric cancer worsens in-hospital death or long-term survival. However, the methodology for PIIC preoperative risk assessment remains unestablished. We aimed to develop a preoperative risk model for postgastrectomy PIIC.

METHODS

We collected 183,936 patients' data on distal or total gastrectomy performed in 2013-2016 for gastric cancer from the Japanese National Clinical Database and divided into development (2013-2015; n = 140,558) and validation (2016; n = 43,378) cohort. The primary outcome was the incidence of PIIC. The risk model for PIIC was developed using 18 preoperative factors: age, sex, body mass index, activities of daily living, 12 comorbidity types, gastric cancer stage, and surgical procedure in the development cohort. Secondarily, we developed another model based on the new scoring system for clinical use using selected factors.

RESULTS

The overall incidence of PIIC was 4.7%, including 2.6%, 1.7%, and 1.3% in anastomotic leakage, pancreatic fistula, and intra-abdominal abscess, respectively. Among the 18 preoperative factors, male [odds ratio, (OR) 1.92], obesity (OR, 1.52-1.96), peripheral vascular disease (OR, 1.55), steroid use (OR, 1.83), and total gastrectomy (OR, 1.89) strongly correlated with PIIC incidence. The entire model using the 18 factors had good discrimination and calibration in the validation cohort. We selected eight relevant factors to create a simple scoring system, using which we categorized the patients into three risk groups, which showed good calibration.

CONCLUSION

Using nationwide clinical practice data, we created a preoperative risk model for postgastrectomy PIIC for gastric cancer.

Asymmetric synthesis of the two enantiomers of β-phosphorus-containing α-amino acids via hydrophosphinylation and hydrophosphonylation of chiral Ni(ii)-complexes

A new approach for the synthesis of the two enantiomers of β-phosphorus-containing α-amino acids was developed via Michael addition of secondary phosphine oxides and dialkyl phosphites to chiral Ni(ii)-complexes of a dehydroalanine-Schiff base.

Asymmetric synthesis of (S)-3-methyleneglutamic acid and its N-Fmoc derivative via Michael addition-elimination reaction of chiral glycine Ni (II) complex with enol tosylates

The use of chiral Ni (II)-complexes of glycine Schiff bases has recently emerged as a leading methodology for asymmetric synthesis of structurally diverse Tailor-Made Amino Acids™, playing a key role in the design of modern pharmaceuticals. Here, we report first example of enantioselective preparation of (S)-3-methyleneglutamic acid and its N-Fmoc derivative via a new type of Michael addition-elimination reaction between chiral nucleophilic glycine equivalent and enol tosylates. This reaction was found to proceed with excellent yield (91%) and diastereoselectivity (>99/1 de) allowing straightforward asymmetric synthesis of (S)-3-methyleneglutamic acid derivatives and analogues. The observed results bode well for general application of this Ni (II) complex approach for preparation and biological studies of this previously unknown type of Tailor-Made Amino Acids™.

Design and synthesis of pyrimidine-5-carbonitrile hybrids as COX-2 inhibitors: Anti-inflammatory activity, ulcerogenic liability, histopathological and docking studies

Two new series of 1,3,4-oxadiazole and coumarin derivatives based on pyrimidine-5-carbonitrile scaffold have been synthesized and evaluated for their COX-1/COX-2 inhibitory activity. Compounds 10c, 10e, 10h-j, 14e-f, 14i and 16 were found to be the most potent and selective inhibitors of COX-2 (IC₅₀ 0.041-0.081 μM, SI 139.74-321.95). Eight compounds were further investigated for their in vivo anti-inflammatory activity. The most active derivatives 10c, 10j and 14e displayed superior in vivo anti-inflammatory activity (% edema inhibition 39.3-48.3, 1 h; 58.4-60.5, 2 h; 70.8-83.2, 3 h; 78.9-89.5, 4 h) to the reference drug celecoxib (% edema inhibition 38.0, 1 h; 48.8, 2 h; 58.4, 3 h; 65.4, 4 h). These derivatives were also tested for their ulcerogenic liability, compound 10j showed better safety profile with reference to celecoxib while 10c and 14e exhibited mild lesions. Molecular docking studies of 10c, 10j, and 14e in the COX-2 active site revealed similar orientation and binding interactions as selective COX-2 inhibitors with a higher liability to access the selectivity side pocket.

Detection of Thiol Functionality and Disulfide Bond Formation by Polyoxometalate

The detection of thiol functionality and intramolecular disulfide bond formation of peptides using the α-Keggin type polyoxometalate molybdenum-oxygen cluster (H₃PMo₁₂O₄₀·nH₂O) is described. Our method entails the addition of this polyoxometalate to solutions of thiol, whereupon the color of the solution changes from colorless to deep blue. Reduction of the polyoxometalate from Mo(VI) to Mo(V) occurs with concomitant oxidation of the thiol functionality, to form disulfide bonds. To exemplify the utility this phenomenon, we accomplished the oxidation of glutathione, reduced linear oxytocin, bactenecin, and α-conotoxin SI; all of which proceeded smoothly and in good conversion in 24 h to less and were accomplished by a change in the color of the reaction solutions.

Cloning, expression, and characterization of a GH 19-type chitinase with antifungal activity from Lysobacter sp. MK9-1

The chitin-assimilating gram-negative bacterium, Lysobacter sp. MK9-1, was isolated from soil and was the source of a glycoside hydrolase family 19-type chitinase (Chi19MK) gene that is 933-bp long and encodes a 311-residue protein. The deduced amino acid sequence of Chi19MK includes a signal peptide, an uncharacterized sequence, a carbohydrate-binding module family 12-type chitin binding domain, and a catalytic domain. The catalytic domain of Chi19MK is approximately 60% similar to those of ChiB from Burkholderia gladioli CHB101, chitinase N (ChiN) from Chitiniphilus shinanonensis SAY3^T, ChiF from Streptomyces coelicolor A3(2), Chi30 from Streptomyces olivaceoviridisis, ChiA from Streptomyces cyaneus SP-27, and ChiC from Streptomyces griseus HUT6037. Chi19MK lacking the signal and uncharacterized sequences (Chi19MKΔNTerm) was expressed in Escherichia coli Rosetta-gami B(DE3), resulting in significant chitinase activity in the soluble fraction. Purified Chi19MKΔNTerm hydrolyzed colloidal chitin and released disaccharide. Furthermore, Chi19MKΔNTerm inhibited hyphal extension in Trichoderma reesei and Schizophyllum commune. Based on quantitative antifungal activity assays, Chi19MKΔNTerm inhibits the growth of Trichoderma viride with an IC₅₀ value of 0.81 μM.

Asymmetric Mannich reactions of (S)-N-tert-butylsulfinyl-3,3,3-trifluoroacetaldimines with yne nucleophiles

In the present work, arylethynes were studied as new C-nucleophiles in the asymmetric Mannich addition reactions with (S)-N-tert-butylsulfinyl-3,3,3-trifluoroacetaldimine. The reactions were conducted under operationally convenient conditions affording the corresponding Mannich adducts with up to 87% yield and 70:30 diastereoselectivity. The isomeric products can be separated using regular column chromatography to afford diastereomerically pure compounds. The purified Mannich addition products were deprotected to give the target enantiomerically pure trifluoromethylpropargylamines. A mechanistic rationale for the observed stereochemical outcome is discussed.

Efficacy of cardiac rehabilitation with motion assistance from wearable cyborg hybrid assistive limb in patients with chronic heart failure: a randomized controlled trial

Background

Recent Cochrane Systematic Review suggested that the participation in cardiac rehabilitation is associated with approximately 20% lower cardiovascular mortality and morbidity. Exercise therapy is the key component of cardiac rehabilitation programs. In recent years, innovative technologies have been introduced into the field of rehabilitation, and a typical example is the wearable cyborg Hybrid Assistive Limb (HAL). The wearable cyborg HAL provides motion assistance based on detection of bioelectrical signals on the skin surface when muscle forces are generated. The lumbar-type HAL is expected to expand the therapeutic options for severe cardiac patients who have difficulty in performing usual cardiac rehabilitation programs, such as bicycle pedaling or walking.

Purpose

We aim to compare the efficacy of exercise therapy performed with motion assistance from a lumbar-type HAL versus conventional training (sit-to-stand exercise without HAL) in patients with chronic heart failure.

Methods

This clinical trial is a randomized, non-blinded, and controlled study. Twenty-eight heart failure patients (73.1±13.8 years) who have difficulty in walking at the usual walking speed of healthy subjects were randomly assigned to 2 groups (HAL group or control group) with a 1:1 allocation ratio and performed sit-to stand exercise either with HAL or without HAL for 5 to 30 minutes once a day, and 6 to 10 days during the study period. The brain natriuretic peptide (BNP), isometric knee extensor strength, standing ability (30-seconds chair-stand test: CS-30), short physical performance battery (SPPB) and 6-minute walking distance (6MWD) were measured before and after the completion of cardiac rehabilitation. Cardiac events such as death, re-hospitalization, myocardial infarction and worsening of angina pectoris and heart failure during 1 year after discharge were evaluated.

Results

There was no significant difference in the number of days of exercise therapy between the two groups. BNP, SPPB and 6MWD were improved in both groups. In the HAL group, the isometric knee extensor strength (0.29±0.11 vs 0.35±0.11 kgf/kg, p=0.003) significantly improved and CS-30 (5.5±5.1 vs 8.2±5.3, p=0.054) tended to improve. However, in the control group, either the isometric knee extensor strength (0.35±0.11 vs 0.36±0.14 kgf/kg, p=0.424) or CS-30 (6.0±4.3 vs 9.2±6.2, p=0.075) did not significantly change. HAL group showed significantly more improvement in the isometric knee extensor strength than control group (p=0.045). Cardiac events occurred in 20% in the HAL group and 43% in the control group.

Conclusion

The improvement in isometric knee extensor strength with the assistance from lumbar-type HAL suggests that exercise therapy using this device may be useful in chronic heart failure patients with flail or sarcopenia, a strong poor prognostic factor in these patients.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This work was supported in part by a grant-in-aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan (JSPS KAKENHI grant number JP17K09485) and funded by the ImPACT Program of the Council for Science, Technology and Innovation (Cabinet Office, Government of Japan) (grant number 2017-PM05-03-01).

Tailor-made amino acid-derived pharmaceuticals approved by the FDA in 2019

Amino acids (AAs) are among a handful of paramount classes of compounds innately involved in the origin and evolution of all known life-forms. Along with basic scientific explorations, the major goal of medicinal chemistry research in the area of tailor-made AAs is the development of more selective and potent pharmaceuticals. The growing acceptance of peptides and peptidomimetics as drugs clearly indicates that AA-based molecules become the most successful structural motif in the modern drug design. In fact, among 24 small-molecule drugs approved by FDA in 2019, 13 of them contain a residue of AA or di-amines or amino-alcohols, which are commonly considered to be derived from the parent AAs. In the present review article, we profile 13 new tailor-made AA-derived pharmaceuticals introduced to the market in 2019. Where it is possible, we will discuss the development form drug-candidates, total synthesis, with emphasis on the core-AA, therapeutic area, and the mode of biological activity.

Design and Evaluation of Anti-SARS-Coronavirus Agents Based on Molecular Interactions with the Viral Protease

Three types of new coronaviruses (CoVs) have been identified recently as the causative viruses for the severe pneumonia-like respiratory illnesses, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and corona-virus disease 2019 (COVID-19). Neither therapeutic agents nor vaccines have been developed to date, which is a major drawback in controlling the present global pandemic of COVID-19 caused by SARS coronavirus 2 (SARS-CoV-2) and has resulted in more than 20,439,814 cases and 744,385 deaths. Each of the 3C-like (3CL) proteases of the three CoVs is essential for the proliferation of the CoVs, and an inhibitor of the 3CL protease (3CL^pro) is thought to be an ideal therapeutic agent against SARS, MERS, or COVID-19. Among these, SARS-CoV is the first corona-virus isolated and has been studied in detail since the first pandemic in 2003. This article briefly reviews a series of studies on SARS-CoV, focusing on the development of inhibitors for the SARS-CoV 3CL^pro based on molecular interactions with the 3CL protease. Our recent approach, based on the structure-based rational design of a novel scaffold for SARS-CoV 3CL^pro inhibitor, is also included. The achievements summarized in this short review would be useful for the design of a variety of novel inhibitors for corona-viruses, including SARS-CoV-2.