Customize Consent Preferences

We use cookies to help you navigate efficiently and perform certain functions. You will find detailed information about all cookies under each consent category below.

The cookies that are categorized as "Necessary" are stored on your browser as they are essential for enabling the basic functionalities of the site. ... 

Always Active

Necessary cookies are required to enable the basic features of this site, such as providing secure log-in or adjusting your consent preferences. These cookies do not store any personally identifiable data.

Functional cookies help perform certain functionalities like sharing the content of the website on social media platforms, collecting feedback, and other third-party features.

Analytical cookies are used to understand how visitors interact with the website. These cookies help provide information on metrics such as the number of visitors, bounce rate, traffic source, etc.

Advertisement cookies are used to provide visitors with customized advertisements based on the pages you visited previously and to analyze the effectiveness of the ad campaigns.

Citation

  • Authors: Pryce KD, Powell R, Agwa D, Evely KM, Sheehan GD, Nip A, Tomasello DL, Gururaj S, Bhattacharjee A.. et al.
  • Year: 2019
  • Journal: FASEB J 33(6): 7315-7330
  • Applications: in vivo / shRNA plasmid / in vivo-jetPEI

Method

The spinal nerve injection protocol was adopted from Chang et al. (37) and optimized for spinal nerve injection in mice. Three days after baseline thermal behavior was established, mice were anesthetized using isoflurane (induction: 4%; maintenance: 2%) and placed in a prone position. A 3-cm posterior longitudinal skin incision was made at the lumbar segment of the spine. The ipsilateral paraspinal muscles were carefully separated, using a pair of sterile toothpicks, from their attachments at the L4 to S1 levels of the vertebral column.A total of 1.5 μl of polyethylenimine–short hairpin RNA (shRNA) plasmid DNA polyplexes at an N/P ratio of 6 was slowly injected directly in the spinal nerve of the right hind paw using a syringe connected to a 26-gauge needle. After injection, the needle was held at the spinal nerve for 1 min to prevent leakage.

Abstract

Voltage-dependent sodium (NaV) 1.8 channels regulate action potential generation in nociceptive neurons, identifying them as putative analgesic targets. Here, we show that NaV1.8 channel plasma membrane localization, retention, and stability occur through a direct interaction with the postsynaptic density-95/discs large/zonula occludens-1–and WW domain–containing scaffold protein called membrane-associated guanylate kinase with inverted orientation (Magi)-1. The neurophysiological roles of Magi-1 are largely unknown, but we found that dorsal root ganglion (DRG)–specific knockdown of Magi-1 attenuated thermal nociception and acute inflammatory pain and produced deficits in NaV1.8 protein expression. A competing cell-penetrating peptide mimetic derived from the NaV1.8 WW binding motif decreased sodium currents, reduced NaV1.8 protein expression, and produced hypoexcitability. Remarkably, a phosphorylated variant of the very same peptide caused an opposing increase in NaV1.8 surface expression and repetitive firing. Likewise, in vivo, the peptides produced diverging effects on nocifensive behavior. Additionally, we found that Magi-1 bound to sequence like a calcium-activated potassium channel sodium-activated (Slack) potassium channels, demonstrating macrocomplexing with NaV1.8 channels. Taken together, these findings emphasize Magi-1 as an essential scaffold for ion transport in DRG neurons and a central player in pain.

Go to