Contrast-enhanced Imaging in Peripheral Pulmonary Lesions: The Role in US-guided Biopsies.

Purpose To compare the tissue adequacy and diagnostic accuracy of US-guided biopsies of peripheral pulmonary lesions (PPLs) with and without contrast agents. Materials and Methods A retrospective study was conducted at four medical centers in patients with PPLs who underwent US-guided percutaneous transthoracic needle biopsy (PTNB) between January 2017 and October 2022. The patients were divided into contrast-enhanced US (CEUS) and US groups based on whether prebiopsy CEUS evaluation was performed. Tissue adequacy and the diagnostic accuracy of PTNB, stratified by lesion size, were analyzed and compared between groups. A propensity score matching (PSM) analysis was conducted using the nearest-neighbor matching method. Results A total of 1027 lesions were analyzed, with 634 patients (mean age, 59.4 years ± 13.0 [SD]; 413 male) in the US group and 393 patients (mean age, 61.2 years ± 12.5; 270 male) in the CEUS group. The CEUS group produced more acceptable samples than the US group (98.2% vs 95.7%; P = .03) and achieved higher diagnostic accuracy (96.9% vs 94.2%; P = .04), with no evidence of a difference in sensitivity (96.7% vs 94.0%; P = .06). PSM and stratified analyses (n = 358 per group) indicated higher tissue adequacy (99.0% vs 95.7%; P = .04) and diagnostic accuracy (98.5% vs 92.9%; P = .006) in the CEUS group compared with the US group for 2-7-cm PPLs but not for lesions larger than 7 cm. Conclusion PTNB with prebiopsy CEUS evaluation demonstrated significantly better tissue adequacy and diagnostic accuracy compared with US guidance alone for PPLs ranging from 2 to 7 cm, with similar biopsy performance achieved between groups for lesions larger than 7 cm. Keywords: Contrast Material, Thoracic Diseases, Ultrasonography, Image-Guided Biopsy © RSNA, 2024.

Diagnostic efficacy of contrast-enhanced gastric ultrasonography in staging gastric cancer: a meta-analysis.

BACKGROUND: As comprehensive surgical management for gastric cancer becomes increasingly specialized and standardized, the precise differentiation between ≤T1 and ≥T2 gastric cancer before endoscopic intervention holds paramount clinical significance. OBJECTIVE: To evaluate the diagnostic efficacy of contrast-enhanced gastric ultrasonography in differentiating ≤T1 and ≥T2 gastric cancer. METHODS: PubMed, Web of Science, and Medline were searched to collect studies published from January 1, 2000 to March 16, 2023 on the efficacy of either double contrast-enhanced gastric ultrasonography (D-CEGUS) or oral contrast-enhanced gastric ultrasonography (O-CEGUS) in determining T-stage in gastric cancer. The articles were selected according to specified inclusion and exclusion criteria, and the quality of the included literature was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 scale. Meta-analysis was performed using Stata 12 software with data from the 2 × 2 crosslinked tables in the included literature. RESULTS: In total, 11 papers with 1124 patients were included in the O-CEGUS analysis, which revealed a combined sensitivity of 0.822 (95% confidence interval [CI] = 0.753-0.875), combined specificity of 0.964 (95% CI = 0.925-0.983), and area under the summary receiver operating characteristic (sROC) curve (AUC) of 0.92 (95% CI = 0.89-0.94). In addition, five studies involving 536 patients were included in the D-CEGUS analysis, which gave a combined sensitivity of 0.733 (95% CI = 0.550-0.860), combined specificity of 0.982 (95% CI = 0.936-0.995), and AUC of 0.93 (95% CI = 0.91-0.95). According to the I2 and P values ​​of the forest plot, there was obvious heterogeneity in the combined specificities of the included papers. Therefore, the two studies with the lowest specificities were excluded from the O-CEGUS and D-CEGUS analyses, which eliminated the heterogeneity among the remaining literature. Consequently, the combined sensitivity and specificity of the remaining studies were 0.794 (95% CI = 0.710-0.859) and 0.976 (95% CI = 0.962-0.985), respectively, for the O-CEDUS studies and 0.765 (95% CI = 0.543-0.899) and 0.986 (95% CI = 0.967-0.994), respectively, for the D-CEGUS studies. The AUCs were 0.98 and 0.99 for O-CEGUS and D-CEGUS studies, respectively. CONCLUSION: Both O-CEGUS and D-CEGUS can differentiate ≤T1 gastric cancer from ≥T2 gastric cancer, thus assisting the formulation of clinical treatment strategies for patients with very early gastric cancer. Given its simplicity and cost-effectiveness, O-CEGUS is often favored as a staging method for gastric cancer prior to endoscopic intervention.

Abdominal Ultrasonography After Transrectal Filling With Contrast Agents in Colorectal Cancer With Severely Stenotic Lesions.

OBJECTIVE: Abdominal ultrasonography after transrectal filling with contrast agent (AU-TFCA) was retrospectively evaluated with respect to determination of T stage and lesion length in patients with colorectal cancer (CRC) who had previously failed colonoscopy because of severe intestinal stenosis. METHODS: The population comprised 83 patients with CRC with intestinal stenosis and previously failed colonoscopy who underwent AU-TFCA, and in addition contrast-enhanced computed tomography (CECT) and/or magnetic resonance imaging (MRI), 2 wk before surgery. The diagnostic performance of AU-TFCA and CECT/MRI was evaluated relative to the post-operative pathological results (PPRs) by paired sample t-test, receiver operator characteristic (ROC) curve, Pearson's χ2-test and κ and intraclass correlation coefficients. RESULTS: The T staging identified via AU-TFCA, but not CECT/MRI, was relatively consistent with that of the PPRs (linearly weighted κ coefficient: 0.558, p < 0.001, and linearly weighted κ coefficient: 0.237, p < 0.001, respectively). The overall diagnostic accuracy of T staging based on AU-TFCA (83.1%) was significantly higher than that based on CECT/MRI (50.6%). Regarding lesion length, the results of AU-TFCA and PPRs were comparable (t = 1.852, p = 0.068), but those of CECT/MRI and PPRs were significantly different (t = 8.450, p < 0.001). CONCLUSION: AU-TFCA is effective in evaluation of lesion length and T stage in patients with severely stenotic CRC lesions who previously failed colonoscopy. The diagnostic accuracy of AU-TFCA is significantly better compared with that of CECT/MRI.

Shenlian (SL) Decoction, a Traditional Chinese Medicine Compound, May Ameliorate Blood Glucose via Mediating the Gut Microbiota in db/db Mice.

Shenlian (SL) decoction is a herbal formula composed of Coptis and ginseng, of which berberine and ginsenoside are the main constituents. Even though SL decoction is widely used in treating diabetes in China, the mechanism of its antidiabetes function still needs further study. Gut microbiota disorder is one of the important factors that cause diabetes. To explore the effect of SL decoction on intestinal microbiota, gut microbiota of mice was analyzed by sequencing the gut bacterial 16S rRNA V3+V4 region and metagenomics. In this study, results demonstrated that SL decoction had a better hypoglycemic effect and ß cell protection effect than either ginseng or Coptis chinensis. Alpha diversity analysis showed that all interventions with ginseng, Coptis, and SL decoction could reverse the increased diversity and richness of gut microbiota in db/db mice. PCoA analysis showed oral SL decoction significantly alters gut microbiota composition in db/db mice. 395 OTUs showed significant differences after SL treatment, of which 37 OTUs enriched by SL decoction showed a significant negative correlation with FBG, and 204 OTUs decreased by SL decoction showed a significant positive correlation with FBG. Results of KEGG analysis and metagenomic sequencing showed that SL decoction could reduce the Prevotellaceae, Rikenellaceae, and Helicobacteraceae, which were related to lipopolysaccharide biosynthesis, riboflavin metabolism, and peroxisome, respectively. It could also upregulate the abundance of Bacteroidaceae, which contributed to the metabolism of starch and sucrose as well as pentose-glucuronate interconversions. In the species level, SL decoction significantly upregulates the relative abundance of Bacteroides_acidifaciens which showed a significant negative correlation with FBG and was reported to be a potential agent for modulating metabolic disorders such as diabetes and obesity. In conclusion, SL decoction was effective in hypoglycemia and its mechanism may be related to regulating gut microbiota via upregulating Bacteroides_acidifaciens.

Probiotics, prebiotics, and synbiotics for the improvement of metabolic profiles in patients with chronic kidney disease: A systematic review and meta-analysis of randomized controlled trials.

This systematic review and meta-analysis of randomized controlled trials (RCTs) was performed to quantify the effects of probiotic, prebiotic, and synbiotic supplementation on biomarkers of inflammation and oxidative stress, as well as lipid profiles among patients with chronic kidney disease (CKD). Electronic databases, including PubMed, the Cochrane Database, and the Web of Science were searched from January 1, 2000, to May 15, 2019. All RCTs that investigated the effect of prebiotics, probiotics, and synbiotics on a circulating (serum and plasma) inflammatory marker (C-reactive protein [CRP]), oxidative stress indicators (malondialdehyde [MDA], glutathione [GSH], and total anti-oxidant capacity [TAC]); and lipid profiles (total cholesterol [TC], triglycerides [TG], low-density lipoprotein cholesterol [LDL-c], and high-density lipoprotein cholesterol [HDL-c]) among patients with CKD were included. Data were pooled and expressed as a standardized mean difference (SMD) with a 95% confidence interval (CI). The protocol for this meta-analysis is registered with PROSPERO; No. CRD42019139090. Thirteen trials that included 671 patients were identified for analysis. The methodological quality varied across studies. Meta-analysis indicated that microbial therapies significantly reduced CRP (SMD, -0.75; 95% CI, -1.03 to -0.47; p = 0.000), MDA (SMD, -1.06; 95% CI, -1.59 to -0.52; p = 0.000), TC (SMD, -0.33; 95% CI, -0.52 to -0.13; p = 0.000), and LDL-c (SMD, -0.44; 95% CI, -0.86 to -0.02; p = 0.000) levels; they also increased the GSH (SMD, 0.44; 95% CI, 0.25 to 0.65; p = 0.000), TAC (SMD, 0.61; 95% CI, 0.07 to 1.15; p = 0.000), and HDL-c (SMD, 0.45; 95% CI, 0.03 to 0.87; p = 0.000) levels in CKD patients, as compared to the placebo groups; however, there was no statistically significant TG concentration among patients with CKD. Subgroup analyses showed that other key factors, such as the duration of intervention, participants' baseline body mass index (BMI), type of intervention, and age, had an effect of microbial therapies on outcomes. This meta-analysis supports the potential use of probiotic, prebiotic, and synbiotic supplements in the improvement of established biomarkers of inflammation and oxidative stress, as well as lipid profiles among patients with CKD, which are well-known cardiovascular risk factors. Further research into these interventions should consider the limitations of our study to explore the effect of long-term administration of these supplements in the CKD population.

Accelerated Kidney Aging in Diabetes Mellitus.

With aging, the kidney undergoes inexorable and progressive changes in structural and functional performance. These aging-related alterations are more obvious and serious in diabetes mellitus (DM). Renal accelerated aging under DM conditions is associated with multiple stresses such as accumulation of advanced glycation end products (AGEs), hypertension, oxidative stress, and inflammation. The main hallmarks of cellular senescence in diabetic kidneys include cyclin-dependent kinase inhibitors, telomere shortening, and diabetic nephropathy-associated secretory phenotype. Lysosome-dependent autophagy and antiaging proteins Klotho and Sirt1 play a fundamental role in the accelerated aging of kidneys in DM, among which the autophagy-lysosome system is the convergent mechanism of the multiple antiaging pathways involved in renal aging under DM conditions. Metformin and the inhibitor of sodium-glucose cotransporter 2 are recommended due to their antiaging effects independent of antihyperglycemia, besides angiotensin-converting enzyme inhibitors/angiotensin receptor blockers. Additionally, diet intervention including low protein and low AGEs with antioxidants are suggested for patients with diabetic nephropathy (DN). However, their long-term benefits still need further study. Exploring the interactive relationships among antiaging protein Klotho, Sirt1, and autophagy-lysosome system may provide insight into better satisfying the urgent medical needs of elderly patients with aging-related DN.

Si-Miao-Yong-An (SMYA) Decoction May Protect the Renal Function Through Regulating the Autophagy-Mediated Degradation of Ubiquitinated Protein in an Atherosclerosis Model.

Hyperlipidemia is common, and its renal toxicity has attracted a great deal of attention. Si-miao-yong-an (SMYA) is a famous ancient decoction of traditional Chinese medicine (TCM), which is still widely used in clinical treatment. In this study, we observed and explored its efficacy and mechanism in protecting renal function in an atherosclerosis model. The results showed that the serum, Cr urinal KIM-1, and NGAL were significantly decreased in SMYA group. Although SMYA failed to alleviate the lipid accumulation, decrease p-NFκB, or increase SOD in kidney tissue, the levels of ubiquitinated protein and P62 were decreased in SMYA group. What is more, a higher LC3 II level was observed in the SMYA group. In conclusion, these data indicated that SMYA decoction may protect renal function in hyperlipidemia via regulating the autophagy-mediated degradation of ubiquitinated protein.

Tripterygium and its extracts for diabetic nephropathy: Efficacy and pharmacological mechanisms.

Diabetic nephropathy (DN) is a common but intractable diabetic microvascular complication. Tripterygium, a Chinses herb, has been proven to be effective for DN treatment. In this review, the efficacy and pharmacological mechanism of tripterygium and its extracts on DN is elucidated. Tripterygium and its extracts could effectively reduce urine protein and protect renal function. Its pharmacological mechanism involves anti-inflammation, anti-oxidation, anti-glomerulosclerosis and anti-fibrosis, which is achieved by balancing the Th1/Th2 cells, regulating macrophage infiltration, and regulating the following pathways: p38 MAPK, NF-κB, TGF-ß, Wnt/ß-catenin, Akt and Notch1. Although tripterygium and its extracts may result in some adverse effects, including liver-function damage, gastrointestinal reaction, menstrual disorders, and reproductive problems, they are considered good alternative medicines for DN if used with caution and in the proper manner.

The effect of probiotic and synbiotic supplementation on biomarkers of inflammation and oxidative stress in diabetic patients: A systematic review and meta-analysis of randomized controlled trials.

The role of gut microbiota in the management of diabetes has been shown. Several current trials are investigating the effect of probiotics and prebiotics, which are widely used to modulate intestinal microbiota, on inflammatory factors and biomarkers of oxidative stress in diabetic patients; however, their findings are controversial. The aim of the current meta-analysis was to evaluate the effects of probiotic and synbiotic supplementation on levels of serum high-sensitivity C-reactive protein (hs-CRP) and biomarkers of oxidative stress in diabetic patients. We searched the PubMed, Web of Science, and The Cochrane Library databases from the inception to October 31, 2018. Randomized controlled trials (RCTs) which reported the effect of probiotics or synbiotics on circulating (serum and plasma) inflammatory marker (hs-CRP) and oxidative stress indicators (malondialdehyde [MDA], glutathione [GSH], nitric oxide [NO], and total antioxidant capacity [TAC]) among patients with diabetes were included. Eligible studies were assessed for risk of bias and subjected to qualitative and quantitative synthesis using either fixed- or random-effects models accounting for clinical heterogeneity. Our meta-analysis identified 16 eligible RCTs (n = 1060). The methodological quality varied across these trials. Pooled data from these trials demonstrated that probiotic and synbiotic consumption significantly decreased hs-CRP level (standardized mean difference [SMD]=-0.38; 95% confidence interval [CI]:-0.51,-0.24; P = 0.000) and MDA (SMD=-0.61; 95% CI: -0.89, -0.32; P = 0.000) in diabetic patients compared to those in subjects receiving placebos. In addition, probiotic and symbiotic supplementation was found to increase TAC (SMD = 0.31; 95% CI: 0.09, 0.52; P = 0.006), NO (SMD, 0.62; 95% CI, 0.25 to 0.99; P = 0.001) and GSH (SMD = 0.41; 95% CI: 0.26, 0.55, P = 0.000) levels. The results of this systematic review and meta-analysis suggest that probiotic and synbiotic supplementation may help to improve biomarkers of inflammation and oxidative stress in diabetic patients. Further studies are needed to develop clinical practice guidelines for the management of inflammation and oxidative stress in these patients.

Yiqihuoxue Formula Activates Autophagy and Offers Renoprotection in a Rat Model of Adenine-Induced Kidney Disease.

Chronic kidney disease (CKD) is a worldwide health problem for which effective therapeutic methods are still lacking. Traditional Chinese medicine (TCM) has been indicated as an effective alternative treatment for kidney disease. In this study, a clinically effective therapy, yiqihuoxue (YQHX) formula, was administrated to adenine-induced kidney disease rats for 6 weeks. We found that the adenine rats displayed a significant reduction in renal function as evidenced by the increased levels of serum creatinine (Scr), blood urea nitrogen (BUN), and 24-h urinary albumin level, which were attenuated by the YQHX treatment. The glomerulosclerosis, interstitial fibrosis, arteriolosclerosis, interstitial inflammation, and tubular dilatation were reversed by the YQHX treatment in the adenine rats. Furthermore, the hepatic damage characterized by increased levels of aspartate aminotransferase and alanine aminotransferase and inflammatory cell infiltration was improved by YQHX. In addition, the number of apoptotic cells in the adenine rats was obviously reduced by the YQHX treatment as manifested by the lower expression level of cleaved caspase-3 protein. Moreover, the YQHX treatment downregulated the expression levels of fibronectin, type I collagen, α-smooth muscle actin, and TGF-ß1 in the adenine rats. Furthermore, autophagy was activated by the YQHX treatment, which manifested as an increased LC3-II and Beclin-1 expression levels and a decreased p62 level. In conclusion, the YQHX formula might retard the progression of kidney disease by activating autophagy.

Effect of Qufengtongluo Decoction on PI3K/Akt Signaling Pathway in the Kidney of Type 2 Diabetes Mellitus Rat (GK Rat) with Diabetic Nephropathy.

Qufengtongluo (QFTL) decoction is an effective treatment for diabetic nephropathy (DN). However, the underlying molecular mechanism is still unclear. In this study, we try to investigate whether QFTL decoction acts via inhibiting PI3K/Akt signaling pathway. Twenty-four GK rats were randomly divided into 3 groups: blank group, sham-operated group, and QFTL group. After model establishment, rats in QFTL group were given QFTL decoction by gavage, while the rest were given pure water. During the 8-week intervention, 24 hr urinal protein was measured every 2-3 weeks. After intervention, kidneys were removed for pathological smear, quantitative real-time PCR, and western blotting to detect expression levels of p-PI3K, p-Akt, PTEN, TGF-ß, PI3K mRNA, Akt mRNA, PTEN mRNA, and TGF-ß mRNA. QFTL group showed a slighter degree of renal fibrosis in Masson and PASM staining and a greater reduction of 24 hr urinal protein than blank group. Compared to blank group, expression levels of p-PI3K, p-Akt, PI3K mRNA, and Akt mRNA were lower in QFTL group, while expression levels of PTEN and PTEN mRNA were higher. Besides, TGF-ß was downregulated by QFTL decoction. In conclusion, this study suggests that QFTL decoction might inhibit PI3K/Akt signaling pathway via activating PTEN and inhibiting TGF-ß.

[Design, synthesis, and biological evaluation of phenylpropenamides compounds as anti-platelet aggregation].

Twenty phenylpropenamide analogs with structural novelty were designed and synthesized upon pharmacophore-combination strategy. The structures of target compounds were elucidated by IR, 1H NMR, 13C NMR and MS, and all the target compounds were biologically evaluated for the inhibitory activities of platelet aggregation induced by adenosine diphoshate（ADP） and（AA） arachidonic acid via Bron method. As a result, compounds 6b, 9b, 9d and 9h demonstrated potent inhibitory activity against platelet aggregation induced by AA. Meanwhile, compounds 6b, 6d, 6j, 9b and 9g exhibited significant suppression of platelet aggregation induced by ADP.

[Synthesis and biological evaluation of novel chalcone aromatic oxygen alkyl acids compounds].

Six novel ligustrazine chalcone aromatic oxygen alkyl acids compounds and two pyridine chalcone aromatic oxygen alkyl acids ester compounds were synthesized according to the traditional Chinese medicine theory removing blood stasis. The structures of target compounds were identified by IR, NMR and ESI-MS. The inhibitory activities of platelet aggregation induced by adenosine diphosphate (ADP) and arachidonic acid(AA) were measured by the liver microsomal incubation method in vitro. Hypolipidemic activities of compounds were tested in vivo for better inhibitory activities of platelet aggregation. Preliminary pharmacological results showed that compounds 7c, 8a and 11 a had potent inhibitory activity against platelet aggregation induced by AA, compounds 7c, 7d, 8a and 11 b showed significant inhibitory activity against platelet aggregation induced by ADP. Compounds 7c and 8a exhibited good hypolipidemic activities in high-fat-diet(HFD) induced hyperlipidemia C57/BL6 mice and worthy for further investigation.

[Novel compound heterozygous mutations of TGM1 gene identified in a Chinese collodion baby].

OBJECTIVE: To identify potential mutations in a Chinese collodion baby. METHODS: The patient was investigated clinically. DNA was extracted from peripheral blood of the baby and his parents. All coding exons(exons 2-15) and splicing sites of transglutaminase 1(TGM1) were amplified by polymerase chain reaction (PCR). Mutation detection was performed by directed sequencing of the PCR products. A total of 100 healthy unrelated subjects were used as controls. Haplotypes were constructed with microsatellites flanking the locus, and TGM1 genotypes of the family were used to determine parental origins of the mutations. CLUSTAL X (1.81) was employed to analyze cross-species conservation of the mutant protein sequence. RESULTS: The boy was found to be a compound heterozygote for two novel mutations: c.420A>G (I140M) from his father and c.832G>A (G278R) from his mother, with the former occurring in the transglutaminase N domain and the latter between transglutaminase N and transglutaminase-like domains. Both mutations were absent from the control subjects. CONCLUSION: The boy's condition was caused by two novel compound heterozygous mutations of c.420A>G and c.832G>A of TGM1. Author's results may provide new clues for molecular diagnosis of this disease.

1-(3,4-Dihy-droxy-phen-yl)hexan-1-one.

In the title compound, C(12)H(16)O(3), a fully extened hexyl carbon chain is attached to a benzene ring; the mean planes formed by the atoms in the benzene ring and the hexa-none are inclined at an angle 8.5 (2)° with respect to each other. In the crystal, inter-molecular O-H⋯O hydrogen bonds join the mol-ecules into an infinite sheet.

R25G mutation in exon 1 of LMNA gene is associated with dilated cardiomyopathy and limb-girdle muscular dystrophy 1B.

BACKGROUND: Mutations of the LMNA gene encoding lamin A and C are associated with dilated cardiomyopathy (DCM), conduction system defects and skeletal muscle dystrophy. Here we report a family with a mutation of the LMNA gene to identify the relationship between genotype and phenotype. METHODS: All 30 members of the family underwent clinical and genetic evaluation. A mutation analysis of the LMNA gene was performed. All of the 12 exons of LMNA gene were extended with polymerase chain reaction (PCR) and the PCR products were screened for gene mutation by direct sequencing. RESULTS: Ten members of the family had limb-girdle muscular dystrophy (LGMD) and 6 are still alive. Two patients suffered from DCM. Cardiac arrhythmias included atrioventricular block and atrial fibrillation; sudden death occurred in 2 patients. The pattern of inheritance was autosomal dominant. Mutation c.73C > G (R25G) in exon 1 encoding the globular domains was confirmed in all of the affected members, resulting in the conversion of arginine (Arg) to glycine (Gly). CONCLUSIONS: The mutation R25G in exon 1 of LMNA gene we reported here in a Chinese family had a phenotype of malignant arrhythmia and mild LGMD, suggesting that patients with familial DCM, conduction system defects and skeletal muscle dystrophy should be screened by genetic testing for the LMNA gene.

Structural analysis of metalloform-selective inhibition of methionine aminopeptidase.

One of the challenges in the development of methionine aminopeptidase (MetAP) inhibitors as antibacterial and anticancer agents is to define the metal ion actually used by MetAP in vivo and to discover MetAP inhibitors that can inhibit the metalloform that is relevant in vivo. Two distinct classes of novel nonpeptidic MetAP inhibitors that are not only potent but also highly selective for either the Mn(II) or Co(II) form have been identified. Three crystal structures of Escherichia coli MetAP complexed with the metalloform-selective inhibitors 5-(2,5-dichlorophenyl)furan-2-carboxylic acid (2), 5-[2-(trifluoromethyl)phenyl]furan-2-carboxylic acid (3) and N-cyclopentyl-N-(thiazol-2-yl)oxalamide (4) have been solved and analysis of these structures has revealed the structural basis for their metalloform-selective inhibition. The Mn(II)-form selective inhibitors (2) and (3) both use their carboxylate group to coordinate with the two Mn(II) ions at the dinuclear metal site and both adopt a non-coplanar conformation for the two aromatic rings. The unique coordination geometry of these inhibitors may determine their Mn(II)-form selectivity. In contrast, the Co(II)-form selective inhibitor (4) recruits an unexpected third metal ion, forming a trimetallic enzyme-metal-inhibitor complex. Thus, an important factor in the selectivity of (4) for the Co(II) form may be a consequence of a greater preference for a softer N,O-donor ligand for the softer Co(II).

Metalloform-selective inhibitors of escherichia coli methionine aminopeptidase and X-ray structure of a Mn(II)-form enzyme complexed with an inhibitor.

Methionine aminopeptidase (MetAP) enzymes require a divalent metal ion such as Mn(II), Fe(II), Co(II), Ni(II), or Zn(II) for its removal of the N-terminal methionine from newly synthesized proteins, but it is not certain which of these ions is most important in vivo. Metalloform-selective MetAP inhibitors could be valuable for defining which metals are physiologically relevant for MetAP activation and could serve as leads for development of new therapeutic agents. We have screened a library of 43 736 small drug-like molecules against Escherichia coli MetAP and identified two groups of potent and highly metalloform-selective inhibitors of the Co(II)-form, and of the Mn(II)-form, of this enzyme. Compound 1 is 790-fold more selective for the Co(II)-form, while compound 4 is over 640-fold more potent toward the Mn(II)-form. The X-ray structure of a di-Mn(II) form of E. coli MetAP complexed with the Mn(II)-form-selective compound 4 was obtained, and it shows that the inhibitor interacts with both Mn(II) ions through the two oxygen atoms of its free carboxylate group. The preferential coordination of the hard (oxygen) donors to Mn(II) may contribute to its superb selectivity toward the Mn(II)-form.