News & Publications

• Sulforaphane inhibits activation of the NLRP3 inflammasome in mice microglia cells. www.sciencedirect.com
  Inflammation Sulforaphane NRF2 NLRP3

  Sulforaphane is a bioactive compound derived from certain cruciferous vegetables, such as broccoli and broccoli sprouts. It exerts potent anti-inflammatory properties and switches on the activity of a vast array of cellular protective proteins. A new study in mice demonstrates that sulforaphane inhibits activation of the NLRP3 inflammasome in mice microglia cells via inhibition of the NF-kB pathway and altered gene expression.

  Inflammasomes are large, intracellular complexes that detect and respond to internal and external threats. Activation of inflammasomes has been implicated in a host of inflammatory disorders. The NLRP3 inflammasome in particular triggers the release of proinflammatory cytokines interleukin-1 beta (IL-1β) and IL-18 and drives pyroptosis, a form of cell death that is triggered by proinflammatory signals and closely linked with inflammation.

  Microglia are the brain’s resident immune cells. They serve an essential role in maintaining brain microenvironment homeostasis. Acute activation of microglia modulates inflammation and neurotoxicity, but chronic activation promotes brain inflammation and damage.

  NF-kB is a family of proteins present in mammalian cells. NF-kB influences several aspects of the body’s stress response via its participation in signaling pathways that drive pro-inflammatory processes, ultimately regulating DNA transcription, cytokine production, cell survival, and immune function.

  The authors of the study triggered the activity of the NLRP3 inflammasome in mice microglia cells that had been treated with or without sulforaphane. Then they assessed the level of pyroptosis in the cells, measured expression of IL-1β and IL-18, and tracked the activity of NF-kB. They also measured the cells' mitochondrial production of reactive oxygen species and mitochondrial membrane integrity. The cells treated with sulforaphane showed less pyroptosis, reduced expression of IL-1β and IL-18, and impaired NF-kB activity than the untreated cells. Sulforaphane also reduced reactive oxygen species production and helped maintain mitochondrial membrane integrity.

  These findings suggest that sulforaphane protects the brain via inhibition of the NF-kB pathway and subsequent inhibition of the NLRP3 inflammasome.

  • Link to study abstract.
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• Increased visceral fat impairs cognition through chronic microglial activation mediated by IL-1 beta release [animal research] www.sciencedaily.com
  Brain Inflammation Memory Fat Dementia Weight Loss NLRP3 Visceral Fat

  Scientists find that visceral fat, a type of adipose tissue that produces high levels of inflammatory signals known as adipokines, impair learning and memory in mice by setting off an inflammatory cascade mediated by the release of IL-1 beta, which crosses the blood-brain barrier leading to chronic activation of microglia.

  From the article:

  “We have identified a specific signal that is generated in visceral fat, released into the blood that gets through the blood brain barrier and into the brain where it activates microglia and impairs cognition.”

  Visceral fat as the ring leader:

  They looked further and found that just transplanting the visceral fat caused essentially the same impact as obesity resulting from a high-fat diet, including significantly increasing brain levels of interleukin-1 beta and activating microglia. Mice missing interleukin-1 beta’s receptor on the microglia also were protected from these brain ravages.

  […]

  To measure cognitive ability, the scientists looked at mice’s ability to navigate a water maze after 12 weeks on a high- or low-fat diet. They found it took the normal, or wild type, mice consuming the higher fat diet as well as the visceral transplant recipients with NLRP3 intact longer to negotiate the water maze. In fact, while they could reach a platform they could see, they had trouble finding one beneath the water’s surface that they had been taught to find. Mice with the interleukin-1 receptor knocked out, could find it just fine, Stranahan says.

  The high-fat diet, transplant mice also had weaker connections, or synapses, between neurons involved in learning and memory. Mice on a high-fat diet but missing NLRP3 were spared these changes, like mice on a low-fat diet.

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