RESUMO
Adult mammalian central nervous system (CNS) trauma interrupts neural networks and, because axonal regeneration is minimal, neurological deficits persist. Repair via axonal growth is limited by extracellular inhibitors and cell-autonomous factors. Based on results from a screen in vitro, we evaluate nearly 400 genes through a large-scale in vivo regeneration screen. Suppression of 40 genes using viral-driven short hairpin RNAs (shRNAs) promotes retinal ganglion cell (RGC) axon regeneration after optic nerve crush (ONC), and most are validated by separate CRISPR-Cas9 editing experiments. Expression of these axon-regeneration-suppressing genes is not significantly altered by axotomy. Among regeneration-limiting genes, loss of the interleukin 22 (IL-22) cytokine allows an early, yet transient, inflammatory response in the retina after injury. Reduced IL-22 drives concurrent activation of signal transducer and activator of transcription 3 (Stat3) and dual leucine zipper kinase (DLK) pathways and upregulation of multiple neuron-intrinsic regeneration-associated genes (RAGs). Including IL-22, our screen identifies dozens of genes that limit CNS regeneration. Suppression of these genes in the context of axonal damage could support improved neural repair.
Assuntos
Regeneração Nervosa/genética , Neurogênese/genética , Traumatismos do Nervo Óptico/genética , Nervo Óptico/metabolismo , Animais , Axônios/metabolismo , Axônios/patologia , Sistemas CRISPR-Cas , Dependovirus/genética , Feminino , Edição de Genes , Regulação da Expressão Gênica , Estudos de Associação Genética , Células HEK293 , Humanos , Interleucinas/genética , Interleucinas/metabolismo , MAP Quinase Quinase Quinases/genética , MAP Quinase Quinase Quinases/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Nervo Óptico/patologia , Nervo Óptico/fisiopatologia , Traumatismos do Nervo Óptico/metabolismo , Traumatismos do Nervo Óptico/patologia , Traumatismos do Nervo Óptico/fisiopatologia , Células Ganglionares da Retina/metabolismo , Células Ganglionares da Retina/patologia , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais , Interleucina 22RESUMO
A case-control study of the effect of antiretroviral therapy (ART) on apoptosis pathway genes comprising 16 cases (HIV infected with mitochondrial toxicity) and 16 controls (HIV uninfected) was conducted. A total of 26 of 84 genes of the apoptosis pathway were differentially expressed. Two of the upregulated genes, DFFA and TNFRSF1A, classified 75% of study participants correctly as either a case or control. Thus, apoptosis may be in the causal pathway of ART-associated mitochondrial toxicity. These two genes could be markers for detecting and monitoring ART-induced mitochondrial toxicity.
Assuntos
Fármacos Anti-HIV/efeitos adversos , Terapia Antirretroviral de Alta Atividade/efeitos adversos , Apoptose/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Infecções por HIV/tratamento farmacológico , Leucócitos Mononucleares/metabolismo , Mitocôndrias/patologia , Adulto , Idoso , Fármacos Anti-HIV/farmacologia , Proteínas Reguladoras de Apoptose/genética , Estudos de Casos e Controles , Citocromos c/sangue , DNA Mitocondrial/efeitos dos fármacos , Feminino , Humanos , Leucócitos Mononucleares/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Mitocôndrias/efeitos dos fármacos , Análise de Componente Principal , Receptores Tipo I de Fatores de Necrose Tumoral/genéticaRESUMO
We found a heterozygous C2857T mutation (R953C) in polymerase gamma (Pol-γ) in an HIV-infected patient with mitochondrial toxicity. The R953C Pol-γ mutant binding affinity for dCTP is 8-fold less than that of the wild type. The R953C mutant shows a 4-fold decrease in discrimination of analog nucleotides relative to the wild type. R953 is located on the "O-helix" that forms the substrate deoxynucleoside triphosphate (dNTP) binding site; the interactions of R953 with E1056 and Y986 may stabilize the O-helix and affect polymerase activity.
