RESUMO
Chronic pain is highly prevalent in the United States, impacting 28.4% of the adult population, or 69.6 million people, as of 2016. Chronic pain is often associated with anxiety, depression, and restrictions in mobility and daily activities, substantially reducing quality of life. Analgesics, especially opioids, are one of the primary pharmaceutical treatment methods for chronic pain. However, prescription opioid misuse and abuse has become increasingly prevalent and concerning, prompting the need for research into alternative treatment methods which avoid the side effects of traditional treatments. Chronic pain is, in part, thought to be the result of oxidative stress and inflammation, and clinical research has indicated links between these conditions and diet. Thus, dietary interventions are a particularly promising therapeutic treatment for chronic pain, with numerous studies suggesting that diet has a noticeable effect on pain as far down as the cellular level. In this review article, data from a number of clinical trials assessing the effect of three diets-antioxidant-rich, low-carbohydrate, and Mediterranean-on oxidative stress and inflammation is compiled and discussed in the context of chronic pain. Clinical data suggests that low-carbohydrate diets and Mediterranean diets both are especially promising dietary interventions.
RESUMO
Nodal-related protein (ndr2) is amember of the transforming growth factor type ß superfamily of factors and is required for ventral midline patterning of the embryonic central nervous system in zebrafish. In humans, mutations in the gene encoding nodal cause holoprosencephaly and heterotaxy. Mutations in the ndr2 gene in the zebrafish (Danio rerio) lead to similar phenotypes, including loss of the medial floor plate, severe deficits in ventral forebrain development and cyclopia. Alleles of the ndr2 gene have been useful in studying patterning of ventral structures of the central nervous system. Fifteen different ndr2 alleles have been reported in zebrafish, of which eight were generated using chemical mutagenesis, four were radiation-induced and the remaining alleles were obtained via random insertion, gene targeting (TALEN) or unknown methods. Therefore, most mutation sites were random and could not be predicted a priori. Using the CRISPR-Cas9 system from Streptococcus pyogenes, we targeted distinct regions in all three exons of zebrafish ndr2 and observed cyclopia in the injected (G0) embryos.We show that the use of sgRNA-Cas9 ribonucleoprotein (RNP) complexes can cause penetrant cyclopic phenotypes in injected (G0) embryos. Targeted polymerase chain reaction amplicon analysis using Sanger sequencing showed that most of the alleles had small indels resulting in frameshifts. The sequence information correlates with the loss of ndr2 activity. In this study, we validate multiple CRISPR targets using an in vitro nuclease assay and in vivo analysis using embryos. We describe one specific mutant allele resulting in the loss of conserved terminal cysteine-coding sequences. This study is another demonstration of the utility of the CRISPR-Cas9 system in generating domain-specific mutations and provides further insights into the structure-function of the ndr2 gene.
