Identification of a new class of activators of the Hippo pathway with antitumor activity in vitro and in vivo

The Hippo pathway is a key regulator of tissue growth, organ size, and tumorigenesis. Activating the Hippo pathway by gene editing or pharmaceutical intervention has been proven to be a new therapeutic strategy for treatment of the Hippo pathway-dependent cancers. To now, a number of compounds that directly target the downstream effector proteins of Hippo pathway, including YAP and TEADs, have been disclosed, but very few Hippo pathway activators are reported. Here, we discovered a new class of Hippo pathway activator, YL-602, which inhibited CTGF expression in cells irrespective of cell density and the presence of serum. Mechanistically, YL-602 activates the Hippo pathway via MST1/2, which is different from known activators of Hippo pathway. In vitro, YL-602 significantly induced tumor cell apoptosis and inhibited colony formation of tumor cells. In vivo, oral administration of YL-602 substantially suppressed the growth of cancer cells by activation of Hippo pathway. Overall, YL-602 could be a promising lead compound, and deserves further investigation for its mechanism of action and therapeutic applications.

Discovery of a novel pyroptosis inhibitor acting though modulating glutathionylation to suppress NLRP3-related signal pathway

Pyroptosis is a proinflammatory type of regulated cell death and has been involved in many pathological processes. Inhibition of pyroptosis is thought to be a promising strategy for the treatment of related diseases. Here, we performed a phenotypic screening against NLRP3-dependent pyroptosis and obtained the novel compound N77 after structure optimization. N77 showed a half-maximal effective concentration (EC50) of 0.070 ± 0.008 μM against cell pyroptosis induced by nigericin, and exhibited a remarkable ability to prevent NLRP3-dependent inflammasome activation and the release of IL-1β. Chemical proteomics revealed the biological target of N77 to be glutathione-S-transferase Mu 1 (GSTM1); our mechanism of action studies indicated that GSTM1 might act as a negative regulator of NLRP3 inflammasome activation by modulating the glutathionylation of caspase-1. In vivo, N77 substantially alleviated the inflammatory reaction in a pyroptosis-related acute keratitis model. Overall, we identified a novel pyroptosis inhibitor and revealed a new regulatory mechanism of pyroptosis. Our findings suggest an alternative potential therapeutic strategy for pyroptosis-related diseases.

Discovery of (S)-3-(4-(benzyloxy)phenyl)-2-(2-phenoxyacetamido)propanoic acid derivatives as a new class of GPR34 antagonists

GPR34 is a rhodopsin-like class G protein-coupled receptor (GPCR) that is involved in the development and progression of several diseases. Despite its importance, effective targeting strategies are lacking. We herein report a series of (S)-3-(4-(benzyloxy)phenyl)-2-(2-phenoxyacetamido)propanoic acid derivatives as a new class of GPR34 antagonists. Structure-activity relationship (SAR) studies led to the identification of the most potent compound, 5e, which displayed an IC50 value of 0.680 μM in the GloSensor cAMP assay and 0.059 μM in the Tango assay. 5e demonstrated low cytotoxicity and high selectivity in vitro, and it was able to dose-dependently inhibit Lysophosphatidylserine-induced ERK1/2 phosphorylation in CHO cells expressing GPR34. Furthermore, 5e displayed excellent efficacy in a mouse model of neuropathic pain without any apparent signs of toxicity. Collectively, this study has identified a promising compound, which shows great potential in the development of potent antagonists with a new chemical scaffold targeting GPR34.

Discovery and structure-activity relationship studies of novel α-ketoamide derivatives targeting the SARS-CoV-2 main protease

The SARS-CoV-2 main protease (Mpro, also named 3CLpro) is a promising antiviral target against COVID-19 due to its functional importance in viral replication and transcription. Herein, we report the discovery of a series of α-ketoamide derivatives as a new class of SARS-CoV-2 Mpro inhibitors. Structure-activity relationship (SAR) of these compounds was analyzed, which led to the identification of a potent Mpro inhibitor (27h) with an IC50 value of 10.9 nM. The crystal structure of Mpro in complex with 27h revealed that α-ketoamide warhead covalently bound to Cys145s of the protease. In an in vitro antiviral assay, 27h showed excellent activity with an EC50 value of 43.6 nM, comparable to the positive control, Nirmatrelvir. This compound displayed high target specificity for Mpro against human proteases and low toxicity. It also possesses favorable pharmacokinetic properties. Overall, compound 27h could be a promising lead compound for drug discovery targeting SARS-CoV-2 Mpro and deserves further in-depth studies.

Cryo-EM structures of human GPR34 enable the identification of selective antagonists

GPR34 is a functional G-protein-coupled receptor of Lysophosphatidylserine (LysoPS), and has pathogenic roles in numerous diseases, yet remains poorly targeted. We herein report a cryo-electron microscopy (cryo-EM) structure of GPR34 bound with LysoPS (18:1) and Gi protein, revealing a unique ligand recognition mode with the negatively charged head group of LysoPS occupying a polar cavity formed by TM3, 6 and 7, and the hydrophobic tail of LysoPS residing in a lateral open hydrophobic groove formed by TM3-5. Virtual screening and subsequent structural optimization led to the identification of a highly potent and selective antagonist (YL-365). Design of fusion proteins allowed successful determination of the challenging cryo-EM structure of the inactive GPR34 complexed with YL-365, which revealed the competitive binding of YL-365 in a portion of the orthosteric binding pocket of GPR34 and the antagonist-binding-induced allostery in the receptor, implicating the inhibition mechanism of YL-365. Moreover, YL-365 displayed excellent activity in a neuropathic pain model without obvious toxicity. Collectively, this study offers mechanistic insights into the endogenous agonist recognition and antagonist inhibition of GPR34, and provides proof of concept that targeting GPR34 represents a promising strategy for disease treatment.

Discovery of benzodiazepine derivatives as a new class of covalent inhibitors of SARS-CoV-2 main protease

The COVID-19 pandemic has caused people immense suffering all over the world. Although the World Health Organization (WHO) has announced the end of the pandemic, the sporadic virus epidemic is still ongoing and may exist permanently. Effective antivirals against SARS-CoV-2 are important to deal with the long-term threat. The main protease (Mpro) is a crucial target for drug development due to its role in the process of virus's replication and transcription. Herein, we report benzodiazepine derivatives as a new class of Mpro inhibitors. Structure-activity relationship (SAR) studies led to the discovery of the most active compound, methyl 10-(2-chloroacetyl)-1-oxo-11-(4-(trifluoromethyl)phenyl)-2,3,4,5,10,11-hexahydro-1H-dibenzo[b,e][1,4]-diazepine-7-carboxylate (11a), which shows an IC50 value of 0.180 ± 0.004 μM. The X-ray crystal structure shows that 11a covalently binds to Mpro. Collectively, we have obtained a new small molecule inhibitor targeting Mpro, which can serve as a lead compound for subsequent drug discovery against SARS-CoV-2.

Discovery of 5-((1H-indazol-3-yl) methylene)-2-thioxoimidazolidin-4-one derivatives as a new class of AHR agonists with anti-psoriasis activity in a mouse model

Aryl hydrocarbon receptor (AHR) is a ligand dependent transcription factor and participates in the regulation of the immune balance of Th17/22 and Treg cells. It has been found to be widely expressed in the skin, and involved in the pathology of psoriasis. Therefore, AHR is thought as a potential intervention target for psoriasis. Here, we report the discovery of 5-((1H-indazol-3-yl) methylene)-2-thioxoimidazolidin-4-one derivatives as a new class of AHR agonists. Structure-activity relationship analyses led to the identification of the most active compound, 5- ((1H-indazol-3-yl)methylene) -3- (prop-2-yn-1-yl) -2-thiooimidazolidin-4-one (24e), which exhibited an EC₅₀ value of 0.015 µM against AHR. Mechanism of action studies showed that 24e regulated the expression of CYP1A1 by activating the AHR pathway. Topical administration of 24e substantially alleviated imiquimod (IMQ)-induced psoriasis-like skin lesion. Overall, compound 24e could be a good lead compound for drug discovery against psoriasis, and hence deserving further in-depth studies.

Discovery of [1,2,3]Triazolo[4,5-c]quinoline Derivatives as a New Class of Ataxia-Telangiectasia Mutated Kinase Inhibitors

Ataxia-telangiectasia mutated (ATM) is an atypical serine/threonine protein kinase which is implicated in the repair of DNA double-strand breaks. Numerous reports have shown that ATM inhibition is an attractive target for radiotherapy and chemotherapy sensitization. Herein we report a new series of ATM kinase inhibitors containing the 1H-[1,2,3]triazolo[4,5-c]quinoline scaffold, which was obtained by virtual screening, structural optimization, and structure-activity relationship studies. Among the inhibitors, A011 was one of the most potent, with an IC₅₀ value of 1.0 nM against ATM. In colorectal cancer cells (SW620 and HCT116), A011 was able to inhibit activation of ATM signaling induced by irinotecan (CPT-11) and ionizing radiation and then increased the sensitivity of colorectal cancer cells to irinotecan and ionizing radiation through increasing G2/M arrest and inducing apoptosis. In the SW620 human colorectal adenocarcinoma tumor xenograft model, A011 sensitized SW620 to CPT-11 by inhibiting ATM activity. Collectively, this work has identified a promising lead in the discovery of potent inhibitors against ATM.

A new generation Mpro inhibitor with potent activity against SARS-CoV-2 Omicron variants

Emerging SARS-CoV-2 variants, particularly the Omicron variant and its sublineages, continually threaten the global public health. Small molecule antivirals are an effective treatment strategy to fight against the virus. However, the first-generation antivirals either show limited clinical efficacy and/or have some defects in pharmacokinetic (PK) properties. Moreover, with increased use of these drugs across the globe, they face great pressure of drug resistance. We herein present the discovery and characterization of a new generation antiviral drug candidate (SY110), which is a potent and selective inhibitor of SARS-CoV-2 main protease (M^pro). This compound displayed potent in vitro antiviral activity against not only the predominant SARS-CoV-2 Omicron sublineage BA.5, but also other highly pathogenic human coronaviruses including SARS-CoV-1 and MERS-CoV. In the Omicron-infected K18-hACE2 mouse model, oral treatment with SY110 significantly lowered the viral burdens in lung and alleviated the virus-induced pathology. Importantly, SY110 possesses favorable PK properties with high oral drug exposure and oral bioavailability, and also an outstanding safety profile. Furthermore, SY110 exhibited sensitivity to several drug-resistance M^pro mutations. Collectively, this investigation provides a promising new drug candidate against Omicron and other variants of SARS-CoV-2.

Discovery of 3-phenyl-1,2,4-oxadiazole derivatives as a new class of SARS-CoV-2 main protease inhibitors

The ongoing COVID-19 pandemic has led to massive infections and deaths and caused tremendous grief among the people. Although vaccines have played an important role in fighting COVID-19, the situation that the protective effect of current vaccines significantly decreases against mutated strains reminds us of the pressing need for developing effective antiviral therapeutics. The main protease (M^pro) is a key enzyme for SARS-CoV-2 viral replication and transcription and an attractive target for drug development. In this research, we report a new series of M^pro inhibitors containing 3-phenyl-1,2,4-oxadiazole. Structure-activity relationship (SAR) studies led to the discovery of the most active compound, 16d, which showed an IC₅₀ value of 5.27 ± 0.26 μM. Collectively, we obtained a new small molecular inhibitor targeting SARS-CoV-2 M^pro, which contains a new scaffold. This compound could be taken as a lead compound for subsequent drug discovery against SARS-CoV-2.

Discovery of 4-(1,2,4-Oxadiazol-5-yl)azepan-2-one Derivatives as a New Class of Cannabinoid Type 2 Receptor Agonists for the Treatment of Inflammatory Pain

Selectively targeting the cannabinoid receptor CB2 is an attractive therapeutic strategy for the treatment of inflammatory pain without psychiatric side effects mediated by the cannabinoid receptor CB1. Herein, we report the discovery of 4-(1,2,4-oxadiazol-5-yl)azepan-2-one derivatives as a new class of CB2 agonists. Systematic structure-activity relationship investigations resulted in the identification of the most potent compound 25r. This compound displayed high selectivity for CB2 against CB1 (CB2 EC₅₀ = 21.0 nM, E_max = 87%, CB1 EC₅₀ > 30 μM, ratio CB1/CB2 > 1428) with favorable pharmacokinetic properties. Especially, 25r demonstrated significant efficacy in the analgesic model of rodent inflammatory pain. All the results suggest that compound 25r could serve as a lead compound for treating inflammatory pain and deserves further in-depth studies.

[Microbiota structure and diversity in Aedes albopictus at different developmental stages]

OBJECTIVE

To investigate the diversity and composition of microflora in laboratory-reared Aedes albopictus at different developmental stages and larval habitat waters.

METHODS

The larval habitat waters and different developmental stages of laboratory-reared A. albopictus were collected, and the V3 and V4 regions of the bacterial 16S rRNA gene were sequenced using Illumina Miseq next-generation sequencing. The abundance and diversity of the microflora were examined using alpha diversity index in A. albopictus at different developmental stages, and the difference in the microflora compositions was compared in A. albopictus at different developmental stages using principal component analysis (PCA). In addition, the species composition and relative abundance of microflora in A. albopictus at different developmental stages were described using histograms and Venn diagrams.

RESULTS

A total of 16 phyla, 30 classes, 72 orders, 129 families and 224 genera of bacteria were detected in larval habitat waters and different developmental stages of A. albopictus. The highest bacterial diversity was seen in larval A. albopictus, with Chao index of 125.20 ± 30.48 and Shannon diversity index of 2.04 ± 0.39, which were comparable to those (Chao index of 118.52 ± 15.07 and Shannon diversity index of 2.15 ± 0.30) in larval habitat waters (t = 0.35 and -0.41, both P values > 0.05). The bacterial abundance and evenness were significantly greater in female adults than in male adults (Chao index: 42.50 ± 3.54 vs. 18.50 ± 2.13, t = 8.23, P < 0.05; Shannon diversity index: 1.25 ± 1.67 vs. 0.50 ± 0.05, t = 6.00, P < 0.05). Proteobacteria, Bacteroidota, Actinobacteriota and Finnicutes were four common phyla of bacteria at each developmental stage of A. albopictus, with Proteobacteria dominated at the pupal stage (90.36%), Bacteroidota dominated at the adult stage (46.01% in female adults and 86.11% in male adults), and Actinobacteriota dominated at the larval stage (32.10%). Elizabethkingia and Rahnella 1 were common dominant genera of bacteria at each developmental stage of A. albopictus, with Rahnellal as the major component at the pupal stage (87.56%), Elizabethkingia as the main component at the adult stage (46.01% in female adults and 86.11% in male adults, respectively), and Microbacteria as the dominant bacterial genus at the larval stage (12.11%). In addition, Delftia, Elizabethkingia, Romboutsia, Serratia, Rahnella 1, Enterococcus and Microbacterium were common genera of bacteria at each developmental stage of A. albopictus, with Edaphobaculum dominated at the larval stage (17.54%) and Sphingobacterium dominated in larval habitat waters (13.93%).

CONCLUSIONS

There are differences in the composition of symbiotic bacteria at different developmental stages of A. albopictus; however, similar microflora diversity is maintained at the phylum level. The microflora diversity is comparable in larvae and larval habitat waters of A. albopictus.

Discovery of a potent, selective and cell active inhibitor of m6A demethylase ALKBH5

AlkB homolog 5 (ALKBH5) is an RNA m⁶A demethylase involved in the regulation of genes transcription, translation and metabolism and has been considered as a promising therapeutic target for various human diseases, especially cancers. However, there is still a lack of potent and selective ALKBH5 inhibitors. Herein, we report a new class of ALKBH5 inhibitors containing the 1-aryl-1H-pyrazole scaffold, which were obtained through fluorescence polarization-based screening, structural optimization and structure-activity relationship analysis. Among these compounds, 20m was the most potent one, which showed an IC₅₀ value of 0.021 μM in fluorescence polarization assay. Compound 20m exhibited high selectivity towards ALKBH5 versus FTO as well as other AlkB subfamily members, indicating good selectivity for ALKBH5. Cellular thermal shift assay (CETSA) analysis showed that 20m could efficiently stabilize ALKBH5 in HepG2 cells. Dot blot assay demonstrated that 20m could increase m⁶A level in intact cells. Collectively, 20m is a potent, selective and cell active ALKBH5 inhibitor and could be used as a versatile chemical probe to explore the biological function of ALKBH5.

Discovery of 6,7-dihydro-5H-pyrrolo[3,4-d] pyrimidine derivatives as a new class of ATR inhibitors

Ataxia telangiectasia and Rad3-related (ATR) kinase is a key regulating protein within the DNA damage response (DDR), responsible for sensing replication stress (RS), and has been considered as a potential target for cancer therapy. Herein, we report the discovery of a series of 6,7-dihydro-5H-pyrrolo[3,4-d]-pyrimidine derivatives as a new class of ATR inhibitors. Among them, compound 5g exhibits an IC₅₀ value of 0.007 μM against ATR kinase. In vitro, 5g displays good anti-tumor activity and could significantly reduce the phosphorylation level of ATR and its downstream signaling protein. Overall, this study provides a promising lead compound for subsequent drug discovery targeting ATR kinase.

Discovery of 3,6-disubstutited-imidazo[1,2-a]pyridine derivatives as a new class of CLK1 inhibitors

Inhibition of cdc2-like kinase1 (CLK1) could efficiently induce autophagy and it has been thought as a potential target for treatment of autophagy-related diseases. Herein we report the discovery of a series of 3,6-disubstutited-imidazo[1,2-a]pyridine derivatives as a new class of CLK1 inhibitors. Among them, compound 9e is the most potent one, which exhibits an IC₅₀ value of 4 nM against CLK1 kinase. In vitro, this compound reduces the phosphorylation level of the typical downstream substrates of CLK1 and affects their subcellular redistribution. Further study indicates that 9e is efficient to induce autophagy. Overall, this study provides a promising lead compound for drug discovery targeting CLK1 kinase.

Transcriptomic analysis reveals the inhibition of reproduction in rice brown planthopper, Nilaparvata lugens, after silencing the gene of MagR (IscA1)

MagR (IscA1) is a member of the iron-sulphur cluster assembly proteins, which plays vital roles in many physiological processes, such as energy metabolism, electron transfer, iron homeostasis, heme biosynthesis and physiologically magnetic response. Its deletion leads to the loss of mitochondrial DNA, inactivation of iron-sulphur proteins and abnormal embryonic development in organisms. However, the physiological roles of MagR in insects are unclear. This study characterized the effects and molecular regulatory mechanism of MagR gene silencing on the reproduction of brachypterous female adults of Nilaparvata lugens. After silencing the MagR gene using RNAi approach, the duration of reproductive period was shortened and the fecundity and hatchability reduced significantly. A total of 479 differentially expressed genes (DEGs) were identified for female adults after 2 days of dsRNA injection through RNA-sequencing technology, including 352 significantly upregulated DEGs and 127 significantly downregulated DEGs, among which 44 DEGs were considered the key genes involved in the effects of NlMagR silencing on the reproduction, revealing the regulatory mechanism of MagR at RNA transcription level and providing a new strategy for the control of N. lugens.

Structure-Guided Discovery of a Potent and Selective Cell-Active Inhibitor of SETDB1 Tudor Domain

SET domain bifurcated protein 1 (SETDB1) is a histone lysine methyltransferase that promotes the silencing of some tumour suppressor genes and is overexpressed in many cancers. SETDB1 contains a unique tandem tudor domain (TTD) that recognizes histone H3 sequences containing both methylated and acetylated lysines. Beginning with the identification of a hit compound (Cpd1), we discovered the first potent and selective small molecule SETDB1-TTD inhibitor (R,R)-59 through stepwise structure-guided optimization. (R,R)-59 showed a K_D value of 0.088±0.045 μM in the ITC assay. The high potency of (R,R)-59 was well explained by the cocrystal structure of the (R,R)-59-TTD complex. (R,R)-59 is an endogenous binder competitive inhibitor. Evidence has also demonstrated its cellular target engagement. Interestingly, the enantiomer (S,S)-59 did not show activity in all the assays, highlighting the potential of (R,R)-59 as a tool compound in exploring the biological functions of SETDB1-TTD.

Ligand recognition and allosteric regulation of DRD1-Gs signaling complexes

Dopamine receptors, including D1- and D2-like receptors, are important therapeutic targets in a variety of neurological syndromes, as well as cardiovascular and kidney diseases. Here, we present five cryoelectron microscopy (cryo-EM) structures of the dopamine D1 receptor (DRD1) coupled to Gs heterotrimer in complex with three catechol-based agonists, a non-catechol agonist, and a positive allosteric modulator for endogenous dopamine. These structures revealed that a polar interaction network is essential for catecholamine-like agonist recognition, whereas specific motifs in the extended binding pocket were responsible for discriminating D1- from D2-like receptors. Moreover, allosteric binding at a distinct inner surface pocket improved the activity of DRD1 by stabilizing endogenous dopamine interaction at the orthosteric site. DRD1-Gs interface revealed key features that serve as determinants for G protein coupling. Together, our study provides a structural understanding of the ligand recognition, allosteric regulation, and G protein coupling mechanisms of DRD1.

When qualitative data contradict quantitative data: diabetes distress in the Chinese-Canadian community

AIMS

To use both quantitative and qualitative approaches to characterize the diabetes distress profile of Chinese-Canadians with Type 2 diabetes and to better understand their experience of living with diabetes.

METHODS

We recruited 40 Chinese-Canadian adults with Type 2 diabetes who completed a Mandarin- or Cantonese-language diabetes education programme in Richmond, British Columbia. Using a mixed-methods sequential explanatory research design, participants first completed a 15-item Chinese version of the Diabetes Distress Scale, which included three subscales: emotional burden, regimen-related distress, and physician distress. The self-report survey was followed by a semi-structured interview that addressed the following diabetes-related topics: perspectives towards the healthcare team, emotional health, diabetes-related concerns and stressors, diabetes diagnosis experience, and sources of social support and diabetes education.

RESULTS

The mean (sd) scores for total distress 1.5 (0.5), emotional burden 1.7 (0.7), regimen-related distress 1.4 (0.5), and physician distress 1.4 (0.9), fell within the 'low distress' range (< 2.0). Qualitative analysis of semi-structured interviews showed that some participants were dissatisfied with diabetes care providers and experienced emotional challenges, particularly early in their diagnosis. Other themes that emerged included eating distress, fear of complications, language barriers, and medication concerns.

CONCLUSIONS

Not only did the qualitative findings from semi-structured interviews capture aspects of diabetes distress that were not included in the quantitative survey, it also uncovered inconsistencies between the two datasets. To more accurately understand the diabetes distress experience of any ethnic community, both quantitative and qualitative approaches contribute unique value.

[A single-center clinical analysis of 65 cases of pseudomyxoma peritonei from appendiceal origin in the early stage]

Objective: To analyze the efficacy and safety of cytoreduction surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) for pseudomyxoma peritonei (PMP) in the early stage. Methods: The clinical data, including pathological features, recurrence and survival of 65 PMP patients in the early stage underwent CRS combined with HIPEC in Aerospace Center Hospital from January, 2011 to December, 2018 were retrospectively analyzed. Results: 65 patients with early stage PMP underwent CRS+ HIPEC. Among these patients, 25 were males and 40 were females, and the mean age was 52.5 years. The median peritoneal cancer index was 3 (0-16). The score of completeness of cytoreduction (CC) of 63 patients (96.9%) was 0, and 2 patients (3.1%) was 1. No perioperative death occurred, the incidence of surgical complications above grade 3 was 3.1%. Three patients relapsed during the follow-up period, including 1 patient with low-grade PMP, 1 patient with high-grade PMP, and 1 patient with high-grade PMP accompanied by signet ring cell. The 5-year disease-free survival rate of the whole group was 92.4%. Conclusions: PMP patients in the early stage treated by CRS combined with HIPEC can achieve benefit and safety. A close long-term follow-up is necessary.

Discovery of 1,8-disubstituted-[1,2,3]triazolo[4,5-c]quinoline derivatives as a new class of Hippo signaling pathway inhibitors

Inhibitors of the Hippo signaling pathway have been demonstrated to have a potential clinical application in cases such as tissue repair and organ regeneration. However, there is a lack of potent Hippo pathway inhibitors at present. Herein we report the discovery of a series of 1,8-disubstituted-[1,2,3]triazolo[4,5-c]quinoline derivatives as a new class of Hippo pathway inhibitors by utilizing a cell line-based screening model (A549-CTGF). Structure-activity relationship (SAR) of these compounds was also discussed. The most potent compound in the A549-CTGF cell assay, 11g, was then evaluated by real-time PCR and immunofluorescence assays. Overall, this study provides a starting point for later drug discovery targeting the Hippo signaling pathway.

Metal-Free Aerobic Oxidative Selective C-C Bond Cleavage in Heteroaryl-Containing Primary and Secondary Alcohols

A transition-metal-free aerobic oxidative selective C-C bond-cleavage reaction in primary and secondary heteroaryl alcohols is reported. This reaction was highly efficient and tolerated various heteroaryl alcohols, generating a carboxylic acid derivative and a neutral heteroaromatic compound. Experimental studies combined with density functional theory calculations revealed the mechanism underlying the selective C-C bond cleavage. This strategy also provides an alternative simple approach to carboxylation reaction.

Compound Poisson approximation for the distribution of extremes

Empirical point processes of exceedances play an important role in extreme value theory, and their limiting behaviour has been extensively studied. Here, we provide explicit bounds on the accuracy of approximating an exceedance process by a compound Poisson or Poisson cluster process, in terms of a Wasserstein metric that is generally more suitable for the purpose than the total variation metric. The bounds only involve properties of the finite, empirical sequence that is under consideration, and not of any limiting process. The argument uses Bernstein blocks and Lindeberg's method of compositions.

The number of two-dimensional maxima

Let n points be placed uniformly at random in a subset A of the plane. A point is said to be maximal in the configuration if no other point is larger in both coordinates. We show that, for large n and for many sets A, the number of maximal points is approximately normally distributed. The argument uses Stein's method, and is also applicable in higher dimensions.

Peripheral Nerve Diffusion Tensor Imaging: Assessment of Axon and Myelin Sheath Integrity

Purpose

To investigate the potential of diffusion tensor imaging (DTI) parameters as in-vivo biomarkers of axon and myelin sheath integrity of the median nerve in the carpal tunnel as validated by correlation with electrophysiology.

Methods

MRI examinations at 3T including DTI were conducted on wrists in 30 healthy subjects. After manual segmentation of the median nerve quantitative analysis of fractional anisotropy (FA) as well as axial, radial and mean diffusivity (AD, RD, and MD) was carried out. Pairwise Pearson correlations with electrophysiological parameters comprising sensory nerve action potential (SNAP) and compound muscle action potential (CMAP) as markers of axon integrity, and distal motor latency (dml) and sensory nerve conduction velocity (sNCV) as markers of myelin sheath integrity were computed. The significance criterion was set at P=0.05, Bonferroni corrected for multiple comparisons.

Results

DTI parameters showed a distinct proximal-to-distal profile with FA, MD, and RD extrema coinciding in the center of the carpal tunnel. AD correlated with CMAP (r=0.50, p=0.04, Bonf. corr.) but not with markers of myelin sheath integrity. RD correlated with sNCV (r=-0.53, p=0.02, Bonf. corr.) but not with markers of axon integrity. FA correlated with dml (r=-0.63, p=0.002, Bonf. corr.) and sNCV (r=0.68, p=0.001, Bonf. corr.) but not with markers of axon integrity.

Conclusion

AD reflects axon integrity, while RD (and FA) reflect myelin sheath integrity as validated by correlation with electrophysiology. DTI parameters consistently indicate a slight decrease of structural integrity in the carpal tunnel as a physiological site of median nerve entrapment. DTI is particularly sensitive, since these findings are observed in healthy participants. Our results encourage future studies to evaluate the potential of DTI in differentiating axon from myelin sheath injury in patients with manifest peripheral neuropathies.

A standard cytogenetic map for Anopheles sinensis and chromosome arm homology between the subgenera Anopheles and Cellia

Anopheles sinensis (Diptera: Culicidae) is an important vector of Plasmodium vivax in Southeast Asia. To facilitate population genetic and genomic studies of An. sinensis, we developed a standard cytogenetic photomap for this species. The polytene chromosomes were straightened and divided into 39 numbered divisions and 116 lettered subdivisions. The chromosomal localizations of 13 DNA probes were determined by fluorescent in situ hybridization. A comparison of the physical map for An. sinensis with the genome map for Anopheles gambiae revealed a whole-arm autosomal translocation between the two species. Specifically, the 2R arm of An. gambiae corresponds to the 3R arm of An. sinensis and the pattern of correspondence of the other chromosome arms remains regular. We mapped the breakpoints of the polymorphic paracentric chromosomal inversion 3Ra to subdivisions 28A and 31A. The standard cytogenetic map developed in this study will be useful for detailed comparative genome mapping and population genetic studies of An. sinensis.

Two fluoradene derivatives: pseudosymmetry, eccentric ellipsoids and a phase transition

Structures of two derivatives of the curved fluoradene ring system (C(19)H(12)) have been determined. Both have phases that are highly pseudosymmetric. At room temperature crystals of 7b-triisopropylsilylfluoradene (C(28)H(32)Si) have a P1 cell that contains two independent molecules (Z' = 2) and that is almost centered. Crystals of 7b-(2,4-dinitrophenyl)fluoradene (C(25)H(14)N(2)O(4)) have both a P2(1)/c cell with Z' = 1 and a P2(1)/c cell with Z' = 2. The molecular volumes in these two P2(1)/c structures differ by 0.7%, but the structures are otherwise virtually the same; the two independent molecules in the larger cell are related by a pseudotranslation. Some of the atomic ellipsoids in the P2(1)/c, Z' = 1 structure are very large and eccentric, and there are some hints in the diffraction pattern of an incipient phase transition, but the Z' = 1 and Z' = 2 phases are clearly different. The P2(1)/c, Z' = 2 crystal at 295 K probably contains some volume fraction of the Z' = 1 phase; when the temperature is lowered to 273 K this fraction is decreased markedly. The pronounced pseudosymmetry in the P1 and P2(1)/c structures that have Z' = 2 has been investigated by analysing the atomic coordinates, by performing refinements in the smaller pseudocells and by making separate Wilson plots for the classes of reflections which are systematically strong and systematically weak. All three approaches are informative, but they reveal different information. Least-squares fits of coordinates of corresponding atoms measure the similarity of the molecular conformations. The Wilson plots allow a quantitative comparison of the intensities of the strong and weak reflections and thus an assessment of the deviations of the true structure from the smaller pseudocell structure. Comparison of the atomic displacements obtained in the full and pseudocell refinements shows where the structural distortions are largest and provides an indication of their directions.

[Two-photon fluorescence from recombinant green fluorescent protein]

The photoconversion process of recombinant green fluorescent protein (rGFP) was investigated by two-photon excitation. The results indicated that the rGFP had very strong two-photon excitation fluorescence. The changes of two-photon-induced fluorescence polarization suggest that there is a proton transfer process between two different proton states of rGFP chromophores. The conformation of rGFP chromophores could be changed upon illumination, which partly block the energy transfer processes from amino acid residues to chromophores in rGFP, and result in the decrease of two-photon-induced fluorescence intensity. The fluorescence from amino acid residues in rGFP was also observed by three-photon excitation, which resulted from the blocked amino acid residues in rGFP. These results suggested that it is necessary to optimize rGFP excitation and detection for quantitative fluorescence microscopy.

Platinum(II) hydrazido complexes

Reaction of 1,2-dimethylhydrazine with the platinum hydroxo complex [(dppp)Pt(mu-OH)](2)(BF(4))(2) gives the bridging 1,2-dimethylhydrazido(-2) product [(dppp)(2)Pt(2)(mu-eta(2):eta(2)-MeNNMe)](BF(4))(2) 1. Crystals of 1.CH(2)Cl(2) from CH(2)Cl(2)/Et(2)O are monoclinic (C/2) with a = 19.690(1), b = 18.886(1), c = 17.170 (1) A, and beta = 92.111(1) degrees. Treatment of [(dppp)Pt(mu-OH)](2)(OTf)(2) with 1,1-dimethylhydrazine gives [(dppp)(2)Pt(2)(mu-OH)(mu-NHNMe(2))](OTf)(2) 2. Crystals of 2.CH(2)Cl(2) from CH(2)Cl(2)/Et(2)O are triclinic (P-1) with a = 12.910 (3), b = 13.927(3), c = 17.5872 (3) A, alpha = 87.121(3), beta = 89.997(4), and gamma = 84.728(3) degrees. Reaction of [(dppp)Pt(mu-OH)](2)(OTf)(2) with 1 equiv of phenylhydrazine in CH(2)Cl(2) gives [(dppp)(2)Pt(2)(mu-OH)(mu-NHNHPh)](OTf)(2) 3. Two equivalents of phenylhydrazine with [(dppp)Pt(mu-OH)](2)(X)(2) gives [(dppp)Pt(mu-NHNHPh)](2)(X)(2) 4 (X = BF(4), OTf). Crystals of 3.ClCH(2)CH(2)Cl from ClCH(2)CH(2)Cl/(i)()Pr(2)O are monoclinic (P2(1)/n) with a = 20.990(2), b = 13.098(1), c = 25.773 (2) A, and beta = 112.944(2) degrees. Crystals of 4(X = BF(4)).ClCH(2)CH(2)Cl(.)()2((t)()BuOMe) from ClCH(2)CH(2)Cl/(t)()BuOMe are monoclinic (C2/m) with a = 30.508(1), b = 15.203(1), c = 19.049 (1) A, and beta = 118.505(2) degrees.

Expression of connexin 30 in the developing mouse cochlea

Mutations in the GJB6 gene encoding connexin 30 (Cx30) can cause dominant forms of nonsyndromic deafness. By studying immunohistochemical localization of Cx30 in the mouse cochlea at different ages from 0 to 30 days after birth, we found that the expression of Cx30 is nearly the same as that of Cx26. These findings suggest that as well as Cx26, Cx30 may also contribute to the generation and maturation of endocochlear potential.

The sequence of the human genome

A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.

Expression of connexin 26 and Na,K-ATPase in the developing mouse cochlear lateral wall: functional implications

The immunohistochemical localization of connexin 26 (a gap junction protein) and Na,K-ATPase in the mouse cochlear lateral wall was studied at different ages between 0 and 30 days after birth (DAB). Connexin 26-like immunoreactivity was sparsely distributed among the connective tissue cells just lateral to the future marginal cells of the stria vascularis on 0 DAB. In the mice of 3-6 DAB, connexin 26 was observed in the strial basal cell area, and was increased in its distribution density on 10 DAB. Connexin 26 was sparsely distributed among the fibrocytes in the spiral ligament and the suprastrial zone on 10 DAB, and its distribution density increased rapidly in the mouse on 12 DAB. The immunohistochemical distribution reached the adult pattern in the cochlear lateral wall on 15 DAB. Weak Na, K-ATPase-like immunoreactivity was observed in the epithelial cells, corresponding to the future strial marginal cells, on 0 DAB. Its staining intensity was enhanced with the increase of age, and reached the adult pattern on 10 DAB. In contrast, Na,K-ATPase-like immunoreactivity in the type II fibrocytes and suprastrial fibrocytes was first detected on 12 DAB, and reached the mature level on 15 DAB. It is well known that the endolymphatic potential (EP) reaches the adult level 2 weeks after birth. The expression patterns of connexin 26 and Na,K-ATPase in the fibrocytes of the spiral ligament and the suprastrial zone coincided with the rapid growth and maturation of EP. These findings may suggest a role for the gap junctional communications and Na,K-ATPase activity of the fibrocytes within the cochlear lateral wall in the generation and maturation of EP.

Trends in anemia treatment with erythropoietin usage and patient outcomes

Recombinant erythropoietin, first approved for Medicare reimbursement in June 1989, was prescribed at initial doses for dialysis patients of 2,500 to 2,700 U per administration independent of hematocrit level. By 1997, however, patients with hematocrits less than 30% were administered 6,000 U/dose, compared with 4,500 U administered to patients with hematocrits of 33% to 36%. Since 1990, the percentage of patients with hematocrits less than 30% decreased from 60% to 22% in 1997, whereas the percentage of patients with hematocrits of 33% to 36% increased from 10% to 30%. In 1997, Medicare initiated the Hematocrit Measurement Audit (HMA) policy, which was directed at reducing the percentage of claims for hematocrits greater than 36% and increasing the stability of the hematocrit levels. The policy change achieved the initial effect but resulted in a reduction of the mean hematocrit as well. The policy was changed in 1998 in response to patient and provider concerns. Mortality studies show that hematocrits less than 30% (or hemoglobin levels < 110 g/L) are associated with an 18% to 40% increased associated risk for death. Higher hematocrits of 33% to 36% appear to be associated with a 7% reduced risk for death. The risk for hospitalization parallels that of mortality. Patients with sustained hematocrits of 33% to 36% over 1 year appear to have the best outcome compared with patients with hematocrits that decrease. The latter are at greater risk than those patients in whom the hematocrits increase. In conclusion, dramatic improvements in hemodialysis patient hematocrits have occurred since 1989. Mortality and hospitalization studies support the National Kidney Foundation Dialysis Outcomes Quality Initiative (NKF DOQI) target hematocrit range of 33% to 36% as providing the best associated outcomes.