Benchtop Nickel Catalysis Invigorated by Electron-Deficient Diene Ligands.

ConspectusDue to the rarity of precious metals like palladium, nickel catalysis is becoming an increasingly important player in organic synthesis, especially for the formation of bonds with sp3-hybridized carbon centers. Traditionally, catalytic processes involving active Ni(0) species have relied on Ni(COD)2 or in situ reduction of Ni(II) salts. However, Ni(COD)2 is an air- and temperature-sensitive material that requires use in an inert-atmosphere glovebox, and in situ reduction protocols of Ni(II) salts using metallic or organometallic reductants add additional complications to reaction development.This Account chronicles the development of air-stable Ni(0) precursors as replacements for Ni(COD)2 or in situ reduction. Based on Schrauzer's seminal discovery of Ni(COD)(DQ) as an air-stable zerovalent organonickel complex, our research laboratories at Scripps Research and Bristol Myers Squibb have developed a class of precatalysts based on the Ni(COD)(EDD) (EDD = electron-deficient diene) framework, relying on the steric and electronic properties of the supporting diene to render the metal center stable to air, moisture, and even silica gel but reactive to ligand substitution and redox changes.The stable Ni(0) complexes can be accessed through ligand exchange with Ni(COD)2, through reduction of Ni(acac)2 using DIBAL-H, or electrochemically via cathodic reduction of Ni(acac)2 to Ni(COD)2, followed by addition of an EDD ligand in one pot. As a toolkit, the complexes demonstrate reactivity that is equivalent or enhanced compared to Ni(COD)2, catalyzing C-C and C-N cross-couplings, Miyaura borylations, C-H activations, and other transformations. Since the initial report on Ni(COD)(DQ), its reactivity in C(sp2)-CN activation, metallophotoredox, and electric field-induced cross-coupling have also been demonstrated.By incorporating the precatalyst toolkit into reaction discovery campaigns, our laboratories have been able to perform C(sp3)-S(alkyl) couplings and metallonitrenoid carboamination, both of which represent challenging transformations that were inaccessible with traditional phosphine, nitrogen, or electron-deficient olefin ligands. Computational and experimental studies demonstrate how the quinone ligands are hemilabile, adopting η1(O)-bound geometries to relieve steric strain or stabilize transition states and intermediates; redox-active, able to transiently oxidize the metal center; and electron-withdrawing or -donating, depending on metal oxidation state and coordination geometry. These studies show how the ligands enable key steps in catalysis beyond imparting air-stability.Since our report documenting the catalytic activity of Ni(COD)(DQ), many other laboratories have also observed unique reactivity with this precatalyst. Ni(COD)(DQ) was found to offer superior reactivity to Ni(COD)2 in C-N cross coupling to form N,N-diaryl sulfonamides and in preparation of biaryls from aryl halides and benzene through a Ni-mediated, base-assisted homolytic aromatic substitution.

Ligand-Promoted Iron-Catalyzed Nitrene Transfer for the Synthesis of Hydrazines and Triazanes through N-Amidation of Arylamines.

Herein, we report that bulky alkylphosphines such as PtBu3 can switch the roles from actor to spectator ligands to promote the FeCl2 -catalyzed N-amidation reaction of arylamines with dioxazolones, giving hydrazides in high efficiency and chemoselectivity. Mechanistic studies indicated that the phosphine ligands could facilitate the decarboxylation of dioxazolones on the Fe center, and the hydrogen bonding interactions between the arylamines and the ligands on Fe nitrenoid intermediates might play a role in modulating the delicate interplay between the phosphine ligand, arylamine, and acyl nitrene N, favoring N-N coupling over N-P coupling. The new ligand-promoted N-amidation protocols offer a convenient way to access various challenging triazane compounds via double or sequential N-amidation of primary arylamines.

MDA5 Enhances Invasive Candida albicans Infection by Regulating Macrophage Apoptosis and Phagocytosis/Killing Functions.

Candida albicans is a common opportunistic pathogenic fungus. The innate immune system provides the first-line host defense against fungal infection. Innate immune receptors and downstream molecules have been shown to play various roles during fungal infection. The innate immune receptor MDA5, encoded by the gene Ifih1, enhances host resistance against viral and Aspergillus fumigatus infection by inducing the production of interferons (IFNs). However, the role of MDA5 in C. albicans infection is still unclear. Here, we found that the gene expression levels of IFIH1 were significantly increased in innate immune cells after C. albicans stimulation through human bioinformatics analysis or mouse experiments. Through in vivo study, MDA5 was shown to enhance host susceptibility to C. albicans infection independent of IFN production. Instead, MDA5 exerted its influence on macrophages and kidneys by modulating the expression of Noxa, Bcl2, and Bax, thereby promoting apoptosis. Additionally, MDA5 compromised killing capabilities of macrophage by inhibition iNOS expression. The introduction of the apoptosis inducer PAC1 further impaired macrophage functions, mimicking the enhancing effect of MDA5 on C. albicans infection. Furthermore, the administration of macrophage scavengers increased the susceptibility of Ifih1-/- mice to C. albicans. The founding suggests that MDA5 promote host susceptibility to invasive C. albicans by enhancing cell apoptosis and compromising macrophage functions, making MDA5 a target to treat candidiasis.

Palladium-Catalyzed Enantioselective Directed C(sp3)-H Functionalization Using C5-Substituted 8-Aminoquinoline Auxiliaries.

8-Aminoquinoline (AQ) has proven to be a highly effective bidentate directing group for palladium-catalyzed C-H functionalization reactions. However, enantiocontrol of AQ-directed C(sp3)-H functionalization reactions has been challenging. Herein, a new protocol is presented for the Pd-catalyzed enantioselective arylation of unactivated ß C(sp3)-H bonds of alkyl carboxamides with aryl iodides using a C5-iodinated 8-aminoquinolines (IQ) auxiliary in conjugation with a BINOL ligand. Additionally, a C5-aryl substituted 8-aminoquinoline auxiliary can facilitate enantioselective alkenylation and alkynylation of benzylic C(sp3)-H bonds of 3-arylpropanamides with the corresponding bromide reagents under similar conditions.

Clinical and whole exome sequencing findings in children from Yunnan Yi minority ethnic group with retinitis pigmentosa: two case reports.

BACKGROUND: Retinitis pigmentosa is a group of rare hereditary retinal dystrophy diseases that lead to difficulty seeing at night, progressive loss of peripheral field vision (tunnel vision), and eventual loss of central vision. However, a genetic cause cannot be determined in approximately 60% of cases. CASE PRESENTATION: Two non-consanguineous Yi minority ethnic group families who have a 6.4-year-old boy and a 0.5-year-old boy, respectively, were recruited for genetic diagnosis. Here, we used whole-exome sequencing to detect mutations in the genes of the probands of the retinitis pigmentosa families, and Sanger sequencing to confirm the causal mutations identified by whole exome sequencing. In addition, we report two cases with retinitis pigmentosa caused by RDH12 (c.524C > T) and PRPF4 (c.1273G > A) pathogenic mutations. CONCLUSIONS: These results might extend the mutation spectrum of known retinitis pigmentosa genes and give these two Yi minority ethnic group families from Yunnan more precise genetic counseling and more specific prognoses.

Molecular characterization of coxsackievirus B5 from the sputum of pneumonia children patients of Kunming, Southwest China.

BACKGROUND: CVB5 can cause respiratory infections. However, the molecular epidemiological information about CVB5 in respiratory tract samples is still limited. Here, we report five cases in which CVB5 was detected in sputum sample of pneumonia children patients from Kunming, Southwest China. METHODS: CVB5 isolates were obtained from sputum samples of patients with pneumonia. Whole-genome sequencing of CVB5 isolates was performed using segmented PCR, and phylogenetic, mutation and recombination analysis. The effect of mutations in the VP1 protein on hydration were analyzed by Protscale. The tertiary models of VP1 proteins were established by Colabfold, and the effect of mutations in VP1 protein on volume modifications and binding affinity were analyzed by Pymol software and PROVEAN. RESULTS: A total of five CVB5 complete genome sequences were obtained. No obvious homologous recombination signals comparing with other coxsackie B viruses were observed in the five isolates. Phylogenetic analysis showed that the five CVB5 sputum isolates were from an independent branch in genogroup E. Due to the mutation, the structure and spatial of the VP1 protein N-terminus have changed significantly. Comparing to the Faulkner (CVB5 prototype strain), PROVEAN revealed three deleterious substitutions: Y75F, N166T (KM35), T140I (KM41). The last two of the three deleterious substitutions significantly increased the hydrophobicity of the residues. CONCLUSIONS: We unexpectedly found five cases of CVB5 infection instead of rhinoviruses infection during our routine surveillance of rhinoviruses in respiratory tract samples. All five patients were hospitalized with pneumonia symptoms and were not tested for enterovirus during their hospitalization. This report suggests that enterovirus surveillance in patients with respiratory symptoms should be strengthened.

Amphetamine-induced neurite injury in PC12 cells through inhibiting GAP-43 pathway.

Amphetamine (AMPH) causes the degeneration of dopamine terminals in the central nervous system. The mechanisms for this damage are unclear. We found AMPH reduced level of GAP-43 in the striatum of rats that receives rich dopaminergic terminals. Using PC12 cells as dopaminergic neuronal models, we further found that AMPH inhibited GAP-43 and GAP-43 phosphorylation in PC12 cells. The reduced GAP-43 was correlated with neurite injury of PC12 cells. The PKCß1, an upstream molecule of GAP-43, was also inhibited by AMPH. Phorbol 12-myristate 13-acetate (PMA) as a specific activator of PKC increased levels of PKCß1 and GAP-43, and efficiently prevented neurite degeneration of PC12 cells induced by AMPH. On the other side, enzastuarin, an inhibitor of PKC, decreased levels of PKCß1 and GAP-43, and caused neurite injury of PC12 cells. Together, our results suggest that AMPH induces neurite injury in PC12 cells through inhibiting PKCß1/GAP-43 pathway.

Directed, nickel-catalyzed 1,2-alkylsulfenylation of alkenyl carbonyl compounds.

We report a regioselective, nickel-catalyzed syn-1,2-carbosulfenylation of non-conjugated alkenyl carbonyl compounds with alkyl/arylzinc nucleophiles and tailored N-S electrophiles. This method allows the simultaneous installation of a variety of C(sp3) and S(Ar) (or Se(Ar)) groups onto unactivated alkenes, which complements previously developed 1,2-carbosulfenylation methodology in which only C(sp2) nucleophiles are compatible. A bidentate directing auxiliary controls regioselectivity, promotes high syn-stereoselectivity with a variety of E- and Z-internal alkenes, and enables the use of an array of electrophilic sulfenyl (and seleno) electrophiles. Among compatible electrophiles, those with N-alkyl-benzamide leaving groups were found to be especially effective, as determined through comprehensive structure-reactivity mapping.

Molecular Characterization of the Viral Structural Genes of Human Rhinovirus A11 from Children Hospitalized with Lower Respiratory Tract Infection in Kunming.

BACKGROUND: The human rhinovirus (HRV) is a picornavirus that can cause a variety of respiratory diseases, including the aggravation of chronic respiratory diseases, such as bronchitis, pneumonia, and asthma. Although an increasing number of lower respiratory tract infection cases have been reported with HRV infection in Europe, few such cases have been reported in China. METHODS: The complete genomic sequences of the HRV-A11 epidemic strains were amplified and obtained by segmented polymerase chain reaction (PCR) and sequence, and then the phylogenetic, nucleotide mutation, recombinant, and comparative analyses of amino acid mutations were performed. RESULTS: Phylogenetic analyses showed that the epidemic strains from 3 rare cases of pneumonia belong to the HRV-A11 subgenotypes. All strains were highly similar to strains from the United States. No obvious homologous recombination signals were observed in the epidemic strains. There were 498 nucleotide and 47 amino acid mutations compared with the HRV-A11 prototype strain. Amino acid mutations were observed at the capsid protein region, P1a, RVA2147-2155, and RVA97-114 epitopes of these clinical strains. CONCLUSIONS: We reported the first case of HRV-A11-associated lower respiratory tract infection in China. These mutations in the P1a, HRV A-specific CD8, and CD4 T-cell epitopes might provide a reference for virological surveillance and vaccine development.

Next generation sequencing of RB1gene for the molecular diagnosis of ethnic minority with retinoblastoma in Yunnan.

BACKGROUND: Retinoblastoma is a rare intraocular malignancy and typically initiated by inactivating biallelic mutations of RB1 gene. Each year, ~ 8000 children worldwide are diagnosed for retinoblastoma. In high-income countries, patient survival is over 95% while low-income countries is ~ 30%.If disease is diagnosed early and treated in centers specializing in retinoblastoma, the survival might exceed 95% and many eyes could be safely treated and support a lifetime of good vision. In China, approximate 1100 newly diagnosed cases are expected annually and 28 hospitals covering 25 provinces established centers classified by expertise and resources for better treatment options and follow-up. Comparing with other province of eastern China, Yunnan province is remote geographically. This might result that healthcare staff have low awareness of the role of genetic testing in management and screening in families. METHODS: The patients with retinoblastoma were selected in Yunnan. DNA from blood was used for targeted gene sequencing. Then, an in-house bioinformatics pipeline was done to detect both single nucleotide variants and small insertions/deletions. The pathogenic mutations were identified and further confirmed by conventional methods and cosegregation in families. RESULTS: Using our approach, targeted next generation sequencing was used to detect the mutation of these 12 probands. Bioinformatic predictions showed that nine mutations were found in our study and four were novel pathogenic variants in these nine mutations. CONCLUSIONS: It's the first report to describe RB1 mutations in Yunnan children with retinoblastoma. This study would improve role of genetic testing for management and family screening.

Clinical and whole-exome sequencing findings in two siblings from Hani ethnic minority with congenital glycosylation disorders.

BACKGROUND: PMM2-CDG, is the most common N-linked glycosylation disorder and subtype among all CDG syndromes, which are a series of genetic disorders involving the synthesis and attachment of glycoproteins and glycolipid glycans. The mutations of PMM2-CDG might lead to the loss of PMM2, which is responsible for the conversion of mannose 6- phosphate into mannose 1-phosphate. Most patients with PMM2-CDG have central nervous system involvement, abnormal coagulation, and hepatopathy. The neurological symptoms of PMM2-CDG are intellectual disability (ID), cerebellar ataxia, and peripheral neuropathy. Now, over 100 new CDG cases have been reported. However, each type of CDG is very rare, and CDGs are problematic to diagnose. In addition, few CDGs have been reported in the Chinese population. CASE PRESENTATION: Here we present a Hani ethnic minority family including two siblings with congenital glycosylation disorders. Whole-exome sequencing revealed compound heterozygous for one novel mutation (c.241-242 del variant) and previously reported mutation (c.395 T > C) in gene of PMM2. Two mutations were found in proband and her sibling by whole-exome sequencing. The mutations were identified in this family by Sanger sequencing and no mutations were detected in the normal control. CONCLUSIONS: This is the first report to describe mutations in two siblings of Hani ethnic minority which is one of five ethnic groups found only in Yunnan with a population of more than 1 million.

Characteristics of olfactory ensheathing cells and microarray analysis in Tupaia belangeri (Wagner, 1841).

Tree shrews are most closely related to the primates and so possess a number of advantages in experimental studies; they have been used as an animal model in bacterial and virus infection, cancer, endocrine system disease, and certain nervous system diseases. Their olfactory ensheathing cells (OECs) are able to release several cytokines to promote neuronal survival, regeneration and remyelination. The present study used western blot analysis to identify antibody specificity in protein extracts from whole tree shrew brains to identify the specificity of p75 nerve growth factor receptor (NGFR) derived from rabbits (75 kDa). OECs were cultured and isolated, then stained and identified using the antibodies for p75NGFR. To investigate the capacity of OECs to express cytokines and growth factors, microarray technology was used, and the analysis revealed that OECs were able to express 9,821 genes. Of these genes, 44 genes were from the neurotrophic factor family, which may indicate their potential in transplantation in vivo. The present study considered the function of OECs as revealed by other studies, and may contribute to future research.

Atractylenolide II reverses the influence of lncRNA XIST/miR-30a-5p/ROR1 axis on chemo-resistance of colorectal cancer cells.

This investigation was conducted to elucidate whether atractylenolide II could reverse the role of lncRNA XIST/miR-30a-5p/ROR1 axis in modulating chemosensitivity of colorectal cancer cells. We totally collected 294 pairs of colorectal cancer tissues and adjacent normal tissues and also purchased colorectal cancer cell lines and human embryonic kidney cell line. 5-fluorouracil, cisplatin, mitomycin and adriamycin were designated as the chemotherapies for colorectal cell lines, and atractylenolides were arranged as the Chinese drug. The expressions of XIST, miR-30a-5p and ROR1 were quantified with aid of qRT-PCR or Western blot, and luciferase reporter gene assay was implemented to determine the relationships among XIST, miR-30a-5p and ROR1. Our results demonstrated that XIST and ROR1 expressions were dramatically up-regulated, yet miR-30a-5p expression was down-regulated within colorectal cancer tissues (P < 0.05). The overexpressed XIST and ROR1, as well as under-expressed miR-30a-5p, were inclined to promote viability and proliferation of colorectal cells under the influence of chemo drugs (P < 0.05). In addition, XIST could directly target miR-30a-5p, and ROR1 acted as the targeted molecule of miR-30a-5p. Interestingly, atractylenolides not only switched the expressions of XIST, miR-30a-5p and ROR1 within colorectal cancer cells but also significantly intensified the chemosensitivity of colorectal cancer cells (P < 0.05). Finally, atractylenolide II was discovered to slow down the viability and proliferation of colorectal cancer cells (P < 0.05). In conclusion, the XIST/miR-30a-5p/ROR1 axis could be deemed as pivotal markers underlying colorectal cancer, and administration of atractylenolide II might improve the chemotherapeutic efficacy for colorectal cancer.

Amphetamine Neurotoxicity in PC12 Cells through the PP2A/AKT/GSK3ß Pathway.

Amphetamine (AMPH) abuse can influence neuropsychiatric disorders and cell apoptosis by interfering with the protein kinase B/ glycogen synthase kinase 3 beta (AKT/GSK3ß) pathway. However, the mechanisms underlying this regulation are poorly understood. Using PC12 cells, we found that AMPH inhibited AKT and GSK-3ß phosphorylation levels and increased total GSK-3ß levels. Furthermore, AMPH caused an increase in the activity of protein phosphatase 2 (PP2A), a signaling protein upstream of AKT, which in turn inhibited phosphorylated AKT levels. Okadaic acid, a PP2A inhibitor, protected PC12 cells against AMPH-induced apoptosis. Together, our results suggest that the PP2A/AKT/GSK3ß pathway plays an important role in AMPH-induced neurotoxicity.

A novel variant in MITF in a child from Yunnan-Guizhou Plateau with autosomal dominant inheritance of nonsyndromic hearing loss: A case report.

Deafness and hearing loss may have functional, economic, social and emotional impacts on humans, including the ability of an individual to communicate with others, feelings of isolation and frustration, and health sector costs. The World Health Organization reported that there are 32 million children worldwide with hearing loss. In order to investigate genetic mutations in children of 26 nationalities with hearing loss in Yunnan, Sanger sequencing was employed to screen for mutations in four of the most common pathological genes, including gap junction protein ß2 and 3, solute carrier family 26 member 4 and mitochondrial DNA. Whole exome sequencing was used to detect the mutation in the proband of a family in which these four genes were normal. Subsequently, the mutation was identified by Sanger sequencing. The present study reports a novel mutation, c.718C>G; p. (Arg240Gly) in the melanogenesis associated transcription factor gene, in Han people with hearing loss. The results of the present study may provide parents and children an accurate diagnosis, which may allow physicians to how to rehabilitate children's hearing.

CSF-Based Analysis for Identification of Potential Serum Biomarkers of Neural Tube Defects.

The protein composition of cerebrospinal fluid (CSF) in neural tube defects (NTDs) remains unknown. We investigated the protein composition of CSF from 9 infants with NTDs using isobaric tags for relative and absolute quantitation (iTRAQ). We identified 568 proteins in the CSF of infants with spina bifida, which is the most common type of NTD. Among these, 18 proteins were associated with neural tube closure in the CSF during human embryonic neurulation and 5 were involved in NTDs. Based on these results, an animal model was further utilized to investigate early serum biomarkers for NTDs. We found that the myristoylated alanine-rich C-kinase substrate, Kunitz-type protease inhibitor 2, and apolipoprotein B-100 protein levels were decreased in both embryos and the sera of pregnant Sprague-Dawley rats carrying embryos with NTDs. CSF proteins may be useful in the discovery of potential serum biomarkers for NTDs.

[Two New Abietane Type Diterpenes from Pinecones of Pinus griffithii].

Objective: To study the chemical constituents from the pinecones of Pinus griffithii. Methods: The constituents were separated and purified with chromatographic methods,and spectroscopic analysis were employed for structural elucidation. Results: Two new abietane type diterpenes and seven known compounds were isolated from the pinecones of Pinus griffithii,and were identified as 15-hydroxy-7α-methoxy-abiet-8,11,13-trien-18-oic acid( 1),7α,13-dihydroxy-podocarpane-8,11,13-trien-18-oic acid( 2),7,12,13,15-tetrahydroxy-abiet-8( 14)-en-18-oic acid( 3),7ß,15-dihydroxy-abiet-8,11,13-trien-18-oic acid( 4),18-norabiet-8,11,13-trien-4,7,15-triol( 5),15-hydroxy-abiet-8,11,13-trien-18-oic acid( 6),7α-hydroxy-15-methoxy-abiet-8,11,13-trien-18-oic acid( 7),7α-hydroxypodocarpen-8( 14)-en-13-one-18-oic acid( 8), oleanolic acid( 9). Conclusion: Compounds 1,2 are the new abietane type diterpene,and all compounds are isolated from this plant for first time.

[Chemical Constituents from Pueraria alopecuroides Ratten].

OBJECTIVE: To study the chemical constituents from the ratten of Pueraria alopecuroide. METHODS: Column chromatography techniques were used for compounds separation. And their structures were elucidated by physico-chemical properties and means of spectral analysis. RESULTS: Five flavonoids were isolated from Pueraria alopecuroide and their structures were identified as: (3R)-2', 3'-dihydroxy-6,7,4'-trimethoxyisoflavane(1), (3R)-8,2'-dihydroxy-7,4'-dimethoxyisoflavane(2), (3S)-vestitol(3), (3R)-(-)-7,2'-dihydroxy-3',4'-dimethoxyisoflavane(4), and 5,7,4'-trihydroxy-2',3'-dimethoxyisoflavanone(5). CONCLUSION: Compounds 1 5 are isolated from this plant for the first time and compound 1 is a new compound.