RESUMO
Cyrtomiumadenotrichum Y. Nong & R.H. Jiang (Dryopteridaceae), a new species from Guangxi, China, is described and illustrated. This new species is similar to C.nephrolepioides (Christ) Copel., C.obliquum Ching & K. H. Shing ex K. H. Shing, C.sinningense Ching & K. H. Shing ex K. H. Shing and C.calcis Liang Zhang, N.T.Lu & Li Bing Zhang in having erect rhizomes, dense, leathery lamina and rounded sori, but it can be easily distinguishable by its stipe sparsely glandular, base obvious oblique, basiscopic base truncate, acroscopic base auriculate or ovate.
RESUMO
There is a large body of evidence that cellular metabolism governs inflammation, and that inflammation contributes to the progression of atherosclerosis. However, whether mitochondrial DNA synthesis affects macrophage function and atherosclerosis pathology is not fully understood. Here we show, by transcriptomic analyzes of plaque macrophages, spatial single cell transcriptomics of atherosclerotic plaques, and functional experiments, that mitochondrial DNA (mtDNA) synthesis in atherosclerotic plaque macrophages are triggered by vascular cell adhesion molecule 1 (VCAM-1) under inflammatory conditions in both humans and mice. Mechanistically, VCAM-1 activates C/EBPα, which binds to the promoters of key mitochondrial biogenesis genes - Cmpk2 and Pgc1a. Increased CMPK2 and PGC-1α expression triggers mtDNA synthesis, which activates STING-mediated inflammation. Consistently, atherosclerosis and inflammation are less severe in Apoe-/- mice lacking Vcam1 in macrophages. Downregulation of macrophage-specific VCAM-1 in vivo leads to decreased expression of LYZ1 and FCOR, involved in STING signalling. Finally, VCAM-1 expression in human carotid plaque macrophages correlates with necrotic core area, mitochondrial volume, and oxidative damage to DNA. Collectively, our study highlights the importance of macrophage VCAM-1 in inflammation and atherogenesis pathology and proposes a self-acerbating pathway involving increased mtDNA synthesis.
Assuntos
Aterosclerose , DNA Mitocondrial , Inflamação , Macrófagos , Proteínas de Membrana , Placa Aterosclerótica , Molécula 1 de Adesão de Célula Vascular , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Animais , Molécula 1 de Adesão de Célula Vascular/metabolismo , Molécula 1 de Adesão de Célula Vascular/genética , Aterosclerose/metabolismo , Aterosclerose/patologia , Aterosclerose/genética , Macrófagos/metabolismo , Humanos , Inflamação/metabolismo , Inflamação/patologia , Inflamação/genética , Camundongos , Placa Aterosclerótica/patologia , Placa Aterosclerótica/metabolismo , Placa Aterosclerótica/genética , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Masculino , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Camundongos Knockout para ApoE , Transdução de Sinais , Feminino , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismoRESUMO
The APOBEC-AID family of cytidine deaminase prefers single-stranded nucleic acids for cytidine-to-uridine deamination. Single-stranded nucleic acids are commonly involved in the DNA repair system for breaks generated by CRISPR-Cas9. Here, we show in human cells that APOBEC3 can trigger cytidine deamination of single-stranded oligodeoxynucleotides, which ultimately results in base substitution mutations in genomic DNA through homology-directed repair (HDR) of Cas9-generated double-strand breaks. In addition, the APOBEC3-catalyzed deamination in genomic single-stranded DNA formed during the repair of Cas9 nickase-generated single-strand breaks in human cells can be further processed to yield mutations mainly involving insertions or deletions (indels). Both APOBEC3-mediated deamination and DNA-repair proteins play important roles in the generation of these indels. Therefore, optimizing conditions for the repair of CRISPR-Cas9-generated DNA breaks, such as using double-stranded donors in HDR or temporarily suppressing endogenous APOBEC3s, can repress these unwanted mutations in genomic DNA.
Assuntos
Sistemas CRISPR-Cas , Citosina Desaminase/química , Quebras de DNA de Cadeia Dupla , Reparo do DNA , Mutação , Desaminases APOBEC , Citidina/química , Citidina Desaminase/genética , DNA de Cadeia Simples , Células HEK293 , Células HeLa , Humanos , Mutação INDEL , Oligonucleotídeos/genética , RNA Interferente Pequeno/metabolismo , Reparo de DNA por Recombinação , Análise de Sequência de DNARESUMO
APOBECs (apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like) are a family of cytidine deaminases that prefer single-stranded nucleic acids as substrates. Besides their physiological functions, APOBEC family members have been found to cause hypermutations of cancer genomes, which could be correlated with cancer development and poor prognosis. Recently, APOBEC family members have been combined with the versatile CRISPR/Cas9 system to perform targeted base editing or induce hypermutagenesis. This combination improved the CRISPR/Cas9-mediated gene editing at single-base precision, greatly enhancing its usefulness. Here, we review the physiological functions and structural characteristics of APOBEC family members and their roles as endogenous mutators that contribute to hypermutations during carcinogenesis. We also review the various iterations of the APOBEC-CRISPR/Cas9 gene-editing tools, pointing out their features and limitations as well as the possibilities for future developments.