TFEB and autophagy

Two 2024 papers that cited Precondition your defenses with broccoli sprouts, starting with an in vitro study of influences on auditory cell function:

“Although various studies have focused on the effect of oxidative stress on the inner ear as an inducer of age-related hearing loss (ARHL), there are no effective preventive approaches for ARHL.

We focused on the function of TFEB and the impact of intracellular ROS as a potential target for ARHL treatment in a NaAsO2-induced auditory premature senescence model. Our results suggested that short exposure to NaAsO2 leads to DNA damage, lysosomal damage and mitochondrial damage in auditory cells, triggering temporary signals for TFEB transport into the nucleus and, as a result, causing insufficient autophagic flux and declines in lysosomal function and biogenesis and mitochondrial quality.

41420_2024_2139_Fig6_HTML

This is the first report to indicate that the inactivation of TFEB directly causes oxidative stress (NaAsO2)-induced premature auditory senescence and SASP induction via decreases in autophagic flux and lysosomal dysfunction, with a lowered pH at the transcriptional level and, as a consequence, ROS production with decreasing mitochondrial quality in auditory cells. The activator of TFEB might have a pivotal antiaging effect in the inner ear.”

https://www.nature.com/articles/s41420-024-02139-4 “Premature senescence is regulated by crosstalk among TFEB, the autophagy lysosomal pathway and ROS derived from damaged mitochondria in NaAsO2-exposed auditory cells”


These researchers used exposure concentrations and durations that had no relevance to humans. Human irrelevance made it difficult to assess the above graphic that shows both TFEB activation and inactivation as stress-related. “No effective preventive approaches for ARHL” was asserted as a given, although “TFEB activation via transport into the nucleus contributes to anti-senescence activity in auditory cells and represents a new therapeutic target for ARHL” was also stated.

Just like the two papers in Eat broccoli sprouts for your hearing, preconditioning’s importance wasn’t investigated. So this study didn’t have findings about how mild TFEB activation or inactivation might precondition auditory cells for other stress that might damage hearing.


Next is a review of muscle regeneration and autophagy:

“Satellite cells, also known as muscle stem cells when activated, are essential for muscle repair. These adult stem cells typically remain in a dormant state. In response to tissue injury, these cells are rapidly activated and divided to generate new stem cells, which proliferate to form myoblasts, which further differentiate into myocytes to repair damaged muscle tissue. However, muscle regeneration can be significantly impaired under various conditions due to dysfunctional satellite cell activity.

mTORC1 activity is suppressed during amino acid starvation, leading to autophagy activation. Under these conditions, TFEB, TFE3, and MITF translocate to the nucleus, where they enhance the transcription of genes involved in autophagy and lysosomal function. When nutrients are abundant, mTORC1 suppresses autophagy. This inhibition ensures that resources are directed toward growth and proliferation rather than cellular recycling.

Chronic injuries are typically associated with sustained metabolic or oxidative stress, leading to prolonged or impaired autophagy. While autophagy serves a compensatory and beneficial role in acute injuries, its role in chronic muscle diseases is more complex. On the one hand, autophagy alleviates oxidative stress and mitigates aging. On the other hand, dysregulated autophagy may contribute to muscle fibrosis and loss of muscle mass.

The function of autophagy varies across different stages of satellite cell activity. Autophagy:

  1. Maintains cellular homeostasis by clearing damaged organelles.
  2. Preserves the number of satellite cells by antagonizing apoptosis.
  3. Sustains the quiescence of satellite cells by reducing reactive oxygen species (ROS).
  4. Promotes the activation of satellite cells by supplying energy.
  5. Facilitates the differentiation of satellite cells by mitochondrial remodeling.”

ijms-25-11901-g003-550

https://www.mdpi.com/1422-0067/25/22/11901 “Autophagy in Muscle Regeneration: Mechanisms, Targets, and Therapeutic Perspective”


I’ve curated a few other of the 110 papers that cited the 2020 “Sulforaphane activates a lysosome-dependent transcriptional program to mitigate oxidative stress” over the years, to include:

Sulforaphane’s effects on autism and liver disease;

Bridging Nrf2 and autophagy; and

Eat broccoli sprouts to maintain your cells.

7 thoughts on “TFEB and autophagy

  1. Whenever I read studies on the multifaceted benefits of sulforaphane, I tell myself to start growing sprouts, but I’m simply too busy to start growing them. Any ideas of a suitable alternative, which requires less effort?

    • Hi Ole! How is your year wrapping up?
      I take the unencapsulated EnduraCell broccoli sprout powder product when I travel. It has the advantage over encapsulated supplements of being metabolized starting in the mouth rather than further into the GI system. Relying on our hosted gut microbiota to process glucoraphanin into sulforaphane is highly individually variable, 0% to 40% at best.
      Two problems though:
      – It costs a lot; and
      – I’ve noted a few times that the company wasn’t forthcoming about their test results.

    • I haven’t seen anything about moringa on this blog. I’d like the blog owner’s thought on this as well, if you don’t mind (sorry, I don’t know your name, blog owner). Moringin, the isothiocyanate in moringa, is more stable than sulforaphane. Moringa leaves can be powdered and shipped without losing potency. Jed Fahey recommended Kuli Kuli brand. He also said moringin was a stronger activator of Nrf2. (He might have said “may be...”)

      I’ve been alternating two rounded teaspoons of moringa powder with a tablespoon of ground broccoli seeds. Sprouting can be a hassle for sure but if you aren’t going to take anything, perhaps moringa would be worth looking into. It’s easy and cheaper than sulforaphane supplements. There isn’t as much research on it but it does the main things sulforaphane does, such as activating AMPK and Nrf2. The effects downstream should be the similar.

      • Good stuff Oliver! What has been your experience?
        I’ve read multiple papers on moringa and seen it mention in reviews. Not enough to gather an informed opinion, though.

      • Moringa tastes stronger to me but so did radish sprouts. So, that probable doesn’t mean anything. The first dose I took of two rounded teaspoons gave me diarrhea. So, I cut back to one teaspoon for the next dose and took it back up to two teaspoons for the third. I haven’t had another bout of the runs since. That was my first dose of an isothiocyanate in years though. If you’re already taking sulforaphane, there may be some cross tolerance there. I just feel like I’m covering more based by alternating.

        The first time around, back when Rhonda Patrick was first talking about it, I started sprouting broccoli and radish seeds. That lasted about four one-pound bags of seeds. Then, sprouting just got to be too much. This time around I’m hoping to stick to it by taking the easy route. I grind the seeds in a coffee grinder or just take the moringa powder. It’s not a hassle at all. Alternating allows me to be even further below the EU’s upper limit of erucic acid. I don’t really believe it’s harmful in humans. In fact, as one of your posts points out, it may even be beneficial. It’s just nice not to have that sliver out doubt niggling in the back of my mind.

        I actually found your blog by Googling erucic acid and broccoli seeds. A Reddit post was near the top of the results and that post cited one of your blog posts. Google should give more weight to your blog. It’s full of quality curated information. It should come before a Reddit post, which could be anything.

  2. Thanks for the reply. Did you ever get the result from the red radish seed study as an alternative to growing broccoli sprouts?

    • Yes. I tried twice last year, most recently described in Week 189. I just couldn’t stomach them.
      If I had a health condition that isothiocyanates could cure, though, I’d choke them down regardless. It’s too much to eat something habitually that causes an adverse reaction.

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