Memory

Nrf2 Week #7: Immunity

gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Immune system, Memory, Stress , ,

Two reviews of Nrf2 relationships with our two immune systems, starting with adaptive immunity:

“We highlight recent findings about the influence of Keap1 and Nrf2 in development and effector functions of adaptive immune cells, T lymphocytes and B lymphocytes. We summarize Nrf2 research potential and targetability for treating immune pathologies.

Immune cells have mechanisms in place to strike a perfect redox balance, and to modulate levels of ROS differentially during their naive, activated, and effector stages for tailored immune responses. Cells of the lymphoid lineage (T, B, and NK cells) and myeloid lineage (macrophages, granulocytes, dendritic cells, and myeloid-derived suppressor cells) are generated from self-renewing progenitors, hematopoietic stem cell (HSCs) in the bone marrow.

Nrf2 activation in HSCs skews hematopoietic differentiation toward the myeloid lineage at the cost of the lymphoid lineage cells. Nrf2 does not participate in late T cell development leading to generation of single-positive CD4 and CD8 T cells.

ih2200061f2

  • Nrf2 activation supports differentiation of the Th2 subset, regulatory T cells (Tregs), and the NKT2 subset while inhibiting differentiation of Th1, Th17, NKT1, and NKT17 subsets.
  • The absence of or low Nrf2 results in enhanced proinflammatory responses, characterized by differentiation of Th1, Th17, NKT1, and NKT17 subsets, and subdued generation of Th2, Treg, and NKT2 subsets.

Nrf2 activation levels also influence generation of humoral responses.

  • Low Nrf2 levels favor T cell–dependent production of IgG and IgM Abs by activated B cells.
  • High Nrf2 suppresses B cell responses such as differentiation of germinal center B cells and plasma cells.

Nrf2 negatively regulates T–cell mediated inflammatory responses and T-dependent B cell responses.“

https://journals.aai.org/immunohorizons/article/7/4/288/263657/Beyond-Antioxidation-Keap1-Nrf2-in-the-Development “Beyond Antioxidation: Keap1–Nrf2 in the Development and Effector Functions of Adaptive Immune Cells”

And our innate immune system:

“Nrf2 regulates the immune response by interacting directly or indirectly with one or more of the major innate immune signaling components that maintain cellular homeostasis. Toll-like receptors (TLR) signaling can induce Nrf2 activation, and this is primarily found to be through autophagy-mediated degradation of Keap1.

TLR agonists may be considered as stimuli that induce Nrf2 to reduce stress and inflammation, linking the immune and antioxidant pathways. Conversely, Nrf2 activation may restrain TLR-mediated inflammatory response through induction of antioxidant proteins and inhibition of pro-inflammatory cytokines.

Following LPS stimulation, the NF-κB pathway is engaged to initiate a host of pro-inflammatory responses such as IL-6 and interleukin 1 beta (IL-1β) gene expression. Nrf2 induction inhibits LPS-mediated activation of pro-inflammatory cytokines in macrophages.

Inflammasome activation is an essential component of the innate immune response, and is critical for clearance of pathogens or damaged cells through pro-inflammatory cytokine secretion and/or cell-death induction. While Nrf2 activation is in general associated with an anti-inflammatory state, Nrf2 has also been reported to be required for optimal NLRP3 inflammasome activity.

The type-I interferon (IFN) system constitutes an essential part of innate immunity. Type-I IFNs are produced upon recognition of foreign or self-DNA or RNA, and are best-known for inducing an antiviral state through the induction of interferon-stimulated genes. While Nrf2 interferes with IRF3 activation, STING expression, and type-I IFN signaling, none of these crucial players in innate immunity have been demonstrated to be direct targets of Nrf2.

The antiviral effect of Nrf2 activation by 4-OI may use various pathways to limit viral replication that have not been identified yet. It is important to consider that Nrf2-activating metabolites may also act as immunomodulators in a Nrf2-independent manner.

Anti-inflammatory properties of Nrf2 are independent of redox control. Further mechanistic studies are needed to decipher the exact indirect and/or direct interactions between Nrf2 and innate immune players.”

https://www.sciencedirect.com/science/article/pii/S0952791522000942 “Regulation of innate immunity by Nrf2”

Nrf2 Week #6: Phytochemicals

gettingwell4 4-5 stars Advanced knowledge, Cerebrum, Dopamine, Epigenetics, Hippocampus, Immune system, Limbic system, Memory, Neurochemicals, Stress , , ,

This 2023 review explored Nrf2 relationships with plant chemicals:

“This review focuses on possible mechanisms of Nrf2 activation by natural phytochemicals in preventing or treating chronic diseases, and regulating oxidative stress. Excess oxidative stress is closely related to many kinds of chronic diseases, such as cardiovascular diseases, cancer, neurodegenerative diseases, diabetes, obesity, and other inflammatory diseases.

Mitochondrial dysfunction and hyperglycemia lead to the massive production of ROS, which triggers molecular damage, inflammation, ferroptosis, insulin resistance, and β-cell dysfunction.

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Crosstalk between Keap1-Nrf2-ARE pathway and other signaling pathways endows it with high complexity and significance in the multi-function of phytochemicals. Limited human data makes an urgent need to open the new field of phytochemical-original supplement application in human chronic disease prevention.”

https://www.mdpi.com/2076-3921/12/2/236 “The Regulatory Effect of Phytochemicals on Chronic Diseases by Targeting Nrf2-ARE Signaling Pathway”

Top ten mentions, not including references:

  • 21 Sulforaphane
  • 16 Broccoli
  • 9 Curcumin
  • 5 Resveratrol
  • 5 Green tea catechins
  • 4 Luteolin
  • 3 Garlic
  • 3 Soy isoflavones
  • 3 Lycopene
  • 3 Quercetin

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Nrf2 Week #2: Neurons

gettingwell4 4-5 stars Advanced knowledge, Anterior cingulate cortex, Brain development, Cerebrum, Epigenetics, Hippocampus, Limbic system, Memory, Stress , , , , ,

To follow the Nrf2 Week #1 suggestion that Nrf2 target neurological disorders, this 2023 cell study investigated Nrf2 expression in neurons:

“Oxidative metabolism is inextricably linked to production of reactive oxygen species (ROS), which have the potential to damage all classes of macromolecules. Yet ROS are not invariably detrimental. Several properties make ROS useful signaling molecules, including their potential for rapid modification of proteins and close ties to cellular metabolism.

We used multiple single cell genomic datasets to explore Nrf2 expression and regulation in hundreds of neuronal and non-neuronal cell types in mouse and human. With few exceptions, Nrf2 is expressed at far lower levels in neurons than in non-neuronal support cells in both species.

This pattern is maintained in multiple disease states, and the chromatin accessibility landscape at the Nrf2 locus parallels these expression differences. These results imply that Nrf2 activity is limited in almost all neurons of the mouse and human central nervous system (CNS).

nrf2 expression

We separated cell types into neuron or non-neuronal ‘support’ cell categories. The general ‘support’ term is not meant to minimize the functional relevance of non-neuronal cells in the CNS, but is an umbrella term meant to cover everything from glial cell types (astrocytes, microglia, oligodendrocytes) to endothelial cells.

It is not clear why an important, near ubiquitous cytoprotective transcription factor like Nrf2 remains off in mature neurons, especially considering oxidative stress is a driver of many diseases. The simplest explanation is that Nrf2 activity also disrupts normal function of mature neurons.

ROS play a key role in controlling synaptic plasticity in mature neurons. These activity-dependent changes in synaptic transmission, which are important for learning and memory, are disrupted by antioxidants.

A subset of important Nrf2-targeted antioxidant genes (e.g., Slc3a2, Slc7a11, Nqo1, Prdx1) are also low in neurons. So it is likely that these and/or other Nrf2 targets must remain low or non-ROS-responsive in mature neurons. Future work exploring why this expression pattern persists in mature neurons will inform our models on roles of antioxidant genes in normal neuronal physiology and in neurological disorders.“

https://www.biorxiv.org/content/10.1101/2023.05.09.540014v1.full “Limited Expression of Nrf2 in Neurons Across the Central Nervous System”

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Don’t eat yourself into disease, Part 2

gettingwell4 4-5 stars Advanced knowledge, Dopamine, Epigenetics, Hippocampus, Hypothalamus, Immune system, Limbic system, Memory, Stress , , ,

This blog’s 1000th curation is a 2023 rodent study associating gut microbiota, behavior, memory, and food reward:

“Energy intake and energy expenditure is regulated by the hypothalamus, and is referred to as homeostatic regulation of food intake. The reward system is the non-homeostatic regulation of food intake – pleasure-related consumption of foods enriched in fat and sugar. The pleasure is encoded by dopamine release from dopaminergic neurons projecting from the ventral tegmental area to the striatum, the nucleus accumbens, and the prefrontal cortex.

Food reward can be divided into three components – liking, wanting, and learning:

  • Liking refers to food hedonic value;
  • Wanting to the motivational process to seek out and consume certain foods; and
  • Learning to reinforcing conditioning behavior associated with food intake stimulus.

We confirmed that obese mice have a dysregulation of the learning and the wanting components of  food reward. Our previous data showed that the liking component was transferable through fecal material transplantation.

We demonstrated that gut microbes play a role in the regulation of food reward, and could be responsible for compulsive behavior and excessive motivation to obtain sucrose pellets. Moreover, obese gut microbes affected dopaminergic and opioid markers involved in reward system.

We identified 33HPP (produced exclusively by gut bacteria) as particularly increased in mice recipients of gut microbes from obese mice. We were able to demonstrate its effects as key mediator of the gut-brain axis controlling the reward response to palatable food.”

https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-023-01526-w “Obese-associated gut microbes and derived phenolic metabolite as mediators of excessive motivation for food reward”

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No exit

gettingwell4 4-5 stars Advanced knowledge, Cortisol, Epigenetics, Immune system, Memory, Neurochemicals, Stress, Telomeres ,

This 2023 rodent study investigated aging processes and gut microbiota in crowded conditions:

“Our study provides clear evidence that high-density crowding accelerates the aging process of Brandt’s voles. We also found that ‘high-density microbiota’ promote the aging-related phenotype in voles.

Because we minimized effects of direct fighting on mortality of voles, observed changes in lifespan in this study should mostly represent the natural aging processes of voles.

high-density survival

High density increased the level of stress hormone corticosterone, which disrupted gut microbiota composition by:

  • Decreasing abundance of anti-aging or anti-inflammatory bacterial species; and
  • Increasing the proportion of pathogenic bacteria.

This caused an increase in DNA oxidation and inflammation through upregulation of NF-kB and COX-2 pathways.

Although high-density relief and butyric acid administration interventions could reverse aging-related processes of adult voles, it remains unclear whether they could reverse the aging process in terms of lifespan.

Our results suggest that gut microbiota play a significant role in mediating aging-related processes of voles under high-density conditions, and can be used as a potential therapeutic target for treating stress-related diseases in humans.”

https://onlinelibrary.wiley.com/doi/10.1002/advs.202205346 “Gut Microbiota is Associated with Aging-Related Processes of a Small Mammal Species under High-Density Crowding Stress”

I came across this study by it citing Reversing hair greying for effects of stress interventions.

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Remembering life before birth

gettingwell4 5+ stars Premium, Epigenetics, Immune system, Memory, Stress , , , ,

This 2023 primate study investigated the body’s capability to remember prenatal experiences influencing later life:

“Maternal stressors and other environmental factors affect the developing embryo and fetus in ways that lead to increased susceptibility for chronic disease in later life. Developmental programming of chronic low-grade inflammation plays an important role in onset and progression of these diseases.

Establishing innate immune cell memory involves increased glycolysis, reduced oxidative phosphorylation, and expression of transcription factors which prime for pro-inflammatory activity. This memory relies on propagation of epigenetic modifications that develop in hematopoietic stem and progenitor cells (HSPCs), which can be passed on to progeny immune cells (i.e., macrophages).

These changes persist with altered epigenetic regulation for years after weaning – even when offspring are fed a conventional diet – predisposing offspring to inflammatory disease across their lifespans.

cell memory

Several factors may initiate metabolomic reprogramming in fetal HSPCs:

  • We found increased chromatin accessibility of gene regulatory regions and RNA signatures supporting activation of factors with a major role in regulating macrophage inflammatory activation, including FOS/JUN, NF-κB, C/EBPβ, and STAT6.
  • Our prior work demonstrated a persistently altered histone code in liver tissue from juvenile animals.
  • Maternal diet-supplied lipids, including oleic acid, in hematopoietic tissues may play an important role in priming inflammation and metabolism in fetal HSPCs and bone marrow-derived macrophages with postnatal persistence.

Striking changes in fetal bone marrow and liver HSPCs observed here suggest that the primary driver for developmental programming of inflammation takes place in utero. However, we cannot rule out that exposure to maternal diet during lactation postnatally triggers shifts in microbiome composition or function contributing to inflammation.

Components of maternal diet, rather than maternal obesity per se, are a modifiable risk factor with potential to alter developmental programming of offspring immune systems.”

https://www.cell.com/cell-reports/fulltext/S2211-1247(23)00404-7 “Maternal diet alters long-term innate immune cell memory in fetal and juvenile hematopoietic stem and progenitor cells in nonhuman primate offspring”

And there are other ways we remember everything that happened then and along the way. Big clues are in our out-of-context responses to present day events.

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Eat broccoli sprouts for depression, Part 3

gettingwell4 4-5 stars Advanced knowledge, Cerebrum, Epigenetics, Hippocampus, Hypothalamus, Limbic system, Memory, Stress , , , , ,

Here are two papers published after Part 2 that cited the Part 1 rodent study, starting with a 2023 rodent study performed by several Part 1 coauthors:

“We used a low-dose LPS-induced endotoxaemia model to mimic clinical characteristics of sepsis. We found that adolescent LPS treatment was sufficient to increase levels of inflammatory factor TNF-α in both the medial prefrontal cortex (mPFC) and hippocampus at post-natal day P22.

P21 LPS-treated mice were injected with sulforaphane (SFN) or saline intraperitoneally at P49 and then subjected to subthreshold social defeat stress (SSDS). We found that SFN preventative treatment significantly:

  • Decreased the social avoidance, anhedonia, and behavioural despair detected by the social interaction test, sucrose preference test, tail suspension test, and forced swim test, respectively.
  • Decreased anxiety-like behaviours without affecting locomotor activities.
  • Increased Nrf2 and brain-derived neurotrophic factor (BDNF) levels in the mPFC of P21 LPS-treated mice after SSDS compared with saline control mice.

The above results suggest that activation of the Nrf2-BDNF signalling pathway prevents the effect of adolescent LPS-induced endotoxaemia on stress vulnerability during adulthood.

sulforaphane and stress vulnerability

These results suggest that early adolescence is a critical period during which inflammation can promote stress vulnerability during adulthood. This might be due to increased inflammatory response in the mPFC, and mediated by decreased levels of Nrf2 and BDNF. These findings may shed light on the potential use of SFN as an alternative preventative intervention for inflammation-induced stress vulnerability.”

https://link.springer.com/article/10.1007/s00213-022-06285-4 “Lipopolysaccharide-induced endotoxaemia during adolescence promotes stress vulnerability in adult mice via deregulation of nuclear factor erythroid 2-related factor 2 in the medial prefrontal cortex” (not freely available)

This study demonstrated that adolescent diseases and stresses don’t necessarily develop into adult social problems. A timely intervention may even prevent future adult problems.

The one-time 10 mg/kg sulforaphane dose was the same as Part 1’s dose, a human equivalent of which is (10 mg x .081) x 70 kg = 57 mg.

I’d like to know more about how subjects’ memories of adverse events were retained, and subsequently affected their biology and behavior. Pretty sure limbic structures like the hypothalamus as well as lower brain structures played a part.

A 2022 review summarized what was known up to that time regarding Nrf2 and depression:

“Sulforaphane, an organosulfur compound isolated from Brassicaceae plants, is a potent natural NRF2 activator. Sulforaphane:

  • Exerts antidepressant- and anxiolytic-like activities and inhibits HPA axis and inflammatory response.
  • Has both therapeutic and prophylactic effects on inflammation-related depression.
  • Confers stress resilience.
  • Protects neurons via autophagy and promotes mitochondrial biogenesis by activating Nrf2.”

https://www.sciencedirect.com/science/article/pii/S2213231722002944 “Nrf2: An all-rounder in depression”

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Ancient parasite DNA within us

gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Immune system, Memory, Stress , , , , ,

Two 2023 papers on endogenous retroviruses (ERVs) and aging relationships, starting with the Introduction section of a comprehensive study:

“Several causal determinants of aging-related molecular changes have been identified, such as epigenetic alterations and stimulation of senescence-associated secretory phenotype (SASP) factors. Although the majority of these studies describe aging determinants originating primarily from protein-coding genes, the non-coding part of the genome has started to garner attention as well.

ERVs belonging to long terminal repeat (LTR) retrotransposons are a relic of ancient retroviral infection, fixed in the genome during evolution, comprising about 8% of the human genome. As a result of evolutionary pressure, most human ERVs (HERVs) accumulate mutations and deletions that prevent their replication and transposition function. However, some evolutionarily young subfamilies of HERV proviruses, such as the recently integrated HERVK, maintain open reading frames encoding proteins required for viral particle formation.

In this study, using cross-species models and multiple techniques, we revealed an uncharacterized role of endogenous retrovirus resurrection as a biomarker and driver for aging. Specifically, we identified endogenous retrovirus expression associated with cellular and tissue aging and that the accumulation of HERVK retrovirus-like particles (RVLPs) mediates the aging-promoting effects in recipient cells. More importantly, we can inhibit endogenous retrovirus-mediated pro-senescence effects to alleviate cellular senescence and tissue degeneration in vivo, suggesting possibilities for developing therapeutic strategies to treat aging-related disorders.”

https://www.cell.com/cell/fulltext/S0092-8674(22)01530-6 “Resurrection of endogenous retroviruses during aging reinforces senescence”

This first paper’s foreword summarized their many experiments and findings:

“The study found that HERVK transcripts, viral proteins, and RVLPs were highly activated in prematurely aged human mesenchymal progenitor cells (hPMCs). This was similarly observed in aged human primary fibroblasts and hPMCs. They also discovered that decreasing silencing epigenetic marks DNA methylation and H3K9me3 while increasing H3K36me3 enabled HERVK expression.

erv aging mechanism

These observations also raise several intriguing questions:

  • HERVK is occasionally activated and eventually suppressed under physiological conditions, for example, in human embryonic cells. It would be fascinating to probe the possibility of mimicking physiological conditions in order to turn off the positive feedback between HERVK and senescence.
  • ERVs are hallmarks of aging in different species, including human, primate, and mouse. Future quantification of the absolute physiological level of ERVs across a broad population of various ages might provide further insights into the relationship between ERVs and organismal age.”

https://academic.oup.com/lifemedi/advance-article/doi/10.1093/lifemedi/lnad001/6982772 “Endogenous retroviruses make aging go viral”

Previously curated papers on these subjects include:

A study of our evolutionary remnants

“Repressive epigenetic marks associated with ERVs, particularly LTRs, show a remarkable switch in silencing mechanisms, depending on evolutionary age:

  • Young LTRs tend to be CpG-rich and are mainly suppressed by DNA methylation, whereas
  • Intermediate age LTRs are associated predominantly with histone modifications, particularly histone H3 lysine 9 (H3K9) methylation.
  • Evolutionarily old LTRs are more likely inactivated by accumulation of loss-of-function genetic mutations.”

Starving awakens ancient parasite DNA within us

Reality is sometimes stranger than what fiction writers dream up. 🙂

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Week 144 of Changing to a youthful phenotype with sprouts

gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Immune system, Memory, Stress , ,

Two papers, starting with a 2023 study that investigated the same red radish cultivar as Sulforaphene, a natural analog of sulforaphane:

“Availability of microgreen products is constantly rising, i.e., they are offered for sale in local farmers markets, specialty stores, and in chain grocery stores. Due to the low demands required for their cultivation and easily available LED settings, microgreens are increasingly grown on a small scale in homes and after harvesting, they are stored in kitchen refrigerators at 4 °C.

The aim of this study was to simulate such cultivation and storage conditions to examine antioxidant capacity of home-grown radish microgreens. Seven-day-old radish microgreens, grown under purple and white LED light, were harvested and stored at 4 °C for two weeks.

Measurements of total antioxidant capacity and bioactive substances were conducted on the harvesting day and on the 3rd, 7th, and 14th day of storage. All three radish cultivars (Raphanus sativus L.) with different leaf colorations:

  • Purple radish (R. sativus cult. China Rose, cvP);
  • Red radish (R. sativus cult. Sango, cvR); and
  • Green radish (Raphanus sativus var. longipinnatus, Japanese white or daikon radish, cvG)

were purchased commercially from a local supplier.

The highest contents of total soluble phenolics, proteins, and sugars, dry matter, and monomeric anthocyanin content, as well as higher overall antioxidant capacity determined in the red radish cultivar (cvR), distinguished this cultivar as the most desirable for human consumption regardless of the cultivation light spectrum.”

https://www.mdpi.com/2311-7524/9/1/76 “Antioxidant Capacity and Shelf Life of Radish Microgreens Affected by Growth Light and Cultivars”

A 2021 review summarized what was known about radishes up to then. Here’s part of its Discussion section:

“It is worth considering radish’s organoleptic characteristics since its particular flavor can influence its acceptability among consumers. The main compound associated with its characteristic pungent flavor is raphasatin, which we have found to be the most reported isothiocyanate produced from the breakdown of glucoraphasatin.

Glucoraphasatin ranked as one of the most concentrated glucosinolates in radish, particularly in its sprouts, but also present in other parts like roots and seeds. Pungency differs among radish cultivars, environmental growth factors, agronomic, and cooking practices.”

1-s2.0-S0924224421003058-gr3_lrg

https://www.sciencedirect.com/science/article/pii/S0924224421003058 “Nutritional and phytochemical characterization of radish (Raphanus sativus): A systematic review”

Seeds I’ve sprouted this year so far, left to right – red radish (Sango), broccoli, red cabbage (Red Acre), yellow mustard, oat (Avena sativa):

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Red radish had similar growth characteristics as broccoli. Started with 3.6 grams of seeds, which increased to 22.2 g after three days using the same soaking and rinsing protocol I use for other sprouts.

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The taste of red radish was too sharp for me to eat by themselves, so I combined them with my broccoli / red cabbage / mustard sprout mix. Bumped up microwaving time to 48 seconds in a 1000 W microwave while staying short of the 60°C (140°F) myrosinase cliff.

The whole mix still had a strong radish taste, though. It was as if two whole red radishes were sliced into a small salad.

Can’t add anything more to dampen that taste and expect beneficial compounds to be unaffected. From Week 19:

A 2018 Netherlands study Bioavailability of Isothiocyanates From Broccoli Sprouts in Protein, Lipid, and Fiber Gels found:

“Compared to the control broccoli sprout, incorporation of sprouts in gels led to lower bioavailability for preformed sulforaphane and iberin.”

IAW, eating protein, fats, and fiber along with microwaved broccoli sprouts wouldn’t help. A 2018 review with some of the same researchers Isothiocyanates from Brassica Vegetables-Effects of Processing, Cooking, Mastication, and Digestion offered one possible explanation for protein acting to lower broccoli sprout compounds’ bioavailability:

“In vitro studies show that ITCs can potentially react with amino acids, peptides, and proteins, and this reactivity may reduce the ITC bioavailability in protein‐rich foods. More in vivo studies should be performed to confirm the outcome obtained in vitro.”

Mixing in red radish sprouts also gave me an upset stomach five of the six mornings. So I won’t continue to sprout red radish.

That said, I’d definitely consider sprouting red radish again to accelerate isothiocyanate treatment of problems where symptoms are much worse than an upset stomach, such as:

  • Neurogenerative diseases with their cognitive decline;
  • Immune system disorders;
  • Bacterial and viral infections; and
  • Other damage caused by oxidative stress conditions in eyes, vascular system, kidney function, etc.

Piping in the New Year

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Eat mushrooms every day?

gettingwell4 4-5 stars Advanced knowledge, Cerebrum, Epigenetics, Hippocampus, Immune system, Limbic system, Memory, Stress , , ,

Three 2022 papers on amino acid ergothioneine, starting with a human study:

“We examined temporal relationships between plasma ergothioneine (ET) status and cognition in a cohort of 470 elderly subjects attending memory clinics in Singapore. All participants underwent baseline plasma ET measurements as well as neuroimaging for cerebrovascular disease (CeVD) and brain atrophy. Neuropsychological tests of cognition and function were assessed at baseline and follow-up visits for up to five years.

Lower plasma ET levels were associated with poorer baseline cognitive performance and faster rates of decline in function as well as in multiple cognitive domains including memory, executive function, attention, visuomotor speed, and language. In subgroup analyses, longitudinal associations were found only in non-demented individuals.

Mediation analyses showed that effects of ET on cognition seemed to be largely explainable by severity of concomitant CeVD, specifically white matter hyperintensities, and brain atrophy. Our findings support further assessment of plasma ET as a prognostic biomarker for accelerated cognitive and functional decline in pre-dementia and suggest possible therapeutic and preventative measures.”

https://www.mdpi.com/2076-3921/11/9/1717 “Low Plasma Ergothioneine Predicts Cognitive and Functional Decline in an Elderly Cohort Attending Memory Clinics”

Earlier this year, two of the study’s coauthors put together a collection of 11 ergothioneine papers:

“One catalyst for this upsurge of interest was the discovery in 2005 of a transporter for ET (OCTN1, often now called the ergothioneine transporter, ETT), which accounts for the fact that animals (including humans) take up and avidly retain ET from the diet. The presence of a specific transporter together with the avid retention of ET in the body implies that this compound is important to us.

To quote an old phrase ‘correlation does not imply causation.’ Low ET levels may predispose to disease, but disease could also lead to low ET levels. Possible reasons could include:

  • Alterations in diet due to illness so that less ET is consumed;
  • Decreases in ETT activity in the gut (leading to less ET uptake) or kidney (impairing ET reabsorption) with age and disease.
  • Changes in gut microbiota might influence uptake and accumulation in the body.
  • ET is being consumed as it scavenges oxygen radicals and other reactive oxygen species, the production of which is known to increase in these diseases and during ageing in general.

Only the gold standard of placebo-controlled double-blinded clinical studies can definitively establish the value (if any) of ET in preventing or treating human disease. Several such trials are being planned or in progress; we await the results with interest, and a streak of optimism.”

https://febs.onlinelibrary.wiley.com/doi/10.1002/1873-3468.14350 “Ergothioneine, where are we now?”

One of the collection’s papers focused on what ETT research findings could or could not be replicated:

“ETT is not expressed ubiquitously and only cells with high ETT cell-surface levels can accumulate ET to high concentration. Without ETT, there is no uptake because the plasma membrane is essentially impermeable. We review substrate specificity and localization of ETT, which is prominently expressed in neutrophils, monocytes/macrophages, and developing erythrocytes.

Comparison of transport efficiency (TE) for acknowledged substrates of the ETT. Bar length represents approximate TE of wild-type human ETT.

feb214269-fig-0001-m

We have not found in the literature any other ET transporters. However, it is highly probable that additional ET transporters work in the human body:

  • Uptake of ET from the small intestine into epithelial cells occurs through apically localized ETT. The very hydrophilic ET cannot then exit these cells toward the blood without help – a basolateral efflux transporter is required.
  • After oral administration of 3H-ET, a considerable amount of ET was still absorbed into the body in the ETT KO [knockout] mice. There must be another transporter for apical uptake at least in the small intestine of the mouse.
  • When ET was administered intravenously, ETT KO mice showed no change in ET concentration in the brain compared to wild type. The little ET that enters the brain must therefore pass through the BBB via a different transporter.”

https://febs.onlinelibrary.wiley.com/doi/10.1002/1873-3468.14269 “The ergothioneine transporter (ETT): substrates and locations, an inventory”

It’s persuasive that there’s an evolutionarily conserved transmitter specific to ergothioneine. It isn’t persuasive that this compound once consumed is almost always in stand-by mode to do: what?

Ergothioneine isn’t a substitute for the related glutathione, especially since its supply isn’t similarly available from an endogenous source. It isn’t an active participant in day-to-day human life.

Still, I hedge my bets. I eat ergothioneine every day via white button mushrooms in AGE-less chicken vegetable soup at a cost of about $1.30.

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What do we know about human aging from mouse models?

gettingwell4 4-5 stars Advanced knowledge, Cortisol, Epigenetics, Hippocampus, Immune system, Limbic system, Memory, Neurochemicals, Stress , ,

Here is a 2021 rodent study and relevant parts from 3 of its 26 citing papers:

“A long line of evidence has established the laboratory mouse as the prime model of human aging. However, relatively little is known about detailed behavioral and functional changes that occur across their lifespan, and how this maps onto the phenotype of human aging.

To better understand age-related changes across the lifespan, we characterized functional aging in male C57BL/6J mice of five different ages (3, 6, 12, 18, and 22 months of age) using a multi-domain behavioral test battery. Assessment of functional aging in humans and mice: age-related patterns were determined based on representative data (Table 2), and then superimposed onto survival rate. (A) Body weight, (B) locomotor activity, (C) gait velocity, (D) grip strength, (E) trait anxiety, (F) memory requiring low attention level, and (G) memory requiring high attention level.

fnagi-13-697621-g012

These functional alterations across ages are non-linear, and patterns are unique for each behavioral trait. Physical function progressively declines, starting as early as 6 months of age in mice, while cognitive function begins to decline later, with considerable impairment present at 22 months of age.

Functional aging of male C57BL/6J mice starts at younger relative ages compared to when it starts in humans. Our study suggests that human-equivalent ages of mice might be better determined on the basis of its functional capabilities.”

https://www.frontiersin.org/articles/10.3389/fnagi.2021.697621/full “Functional Aging in Male C57BL/6J Mice Across the Life-Span: A Systematic Behavioral Analysis of Motor, Emotional, and Memory Function to Define an Aging Phenotype”

“Studies in mice show that physical function (i.e., locomotor activity, gait velocity, grip strength) begins to deteriorate around post-natal day (PND) 180, but cognitive functions (i.e., memory) do not exhibit impairment until roughly PND 660. Our results should be considered within the context of behavior changing throughout vole adulthood. Caution should be taken to avoid categorizing the oldest age group in our study as ‘elderly’ or ‘geriatric.'”

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0276897 “Behavioral trajectories of aging prairie voles (Microtus ochrogaster): Adapting behavior to social context wanes with advanced age”

“We used adult mice ranging in age from 5-6 months, not enough to modify experimental autoimmune encephalomyelitis progression. Mice are considered adult after 8 weeks; however, rapid growth for most biological processes is observed until 3 months of age, while past 6 months, mice might be affected by senescence.”

https://www.frontiersin.org/articles/10.3389/fimmu.2022.1036680/full “Age related immune modulation of experimental autoimmune encephalomyelitis in PINK1 knockout mice”

“Locomotor activity and gait velocity of 12 months old male C57BL/6 correlates with an elderly human being aged 60 or older, supporting that the ~15 months old mice we used in our study were aged mice at the time of tissue collection.”

https://www.mdpi.com/1422-0067/23/20/12461 “Genomic Basis for Individual Differences in Susceptibility to the Neurotoxic Effects of Diesel Exhaust”

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Broccoli sprouts activate the AMPK pathway, Part 4

gettingwell4 4-5 stars Advanced knowledge, Cerebrum, Dopamine, Epigenetics, Hippocampus, Immune system, Limbic system, Memory, Neurochemicals, Stress , , , , ,

Today someone viewed the 2020 Part 3 of Broccoli sprouts activate the AMPK pathway which lacked citations at the time. Checking again, here are three citing 2022 papers, starting with a review:

“Nrf2 is an important transcription factor that regulates expression of a large number of genes in healthy and disease states. Nrf2 regulates expression of several key components of oxidative stress, mitochondrial biogenesis, mitophagy, autophagy, and mitochondrial function in all organs of the human body, and in the peripheral and central nervous systems.

Overall, therapeutic drugs including sulforaphane that target Nrf2 expression and Nrf2/ARE pathway are promising. This article proposes additional research in Nrf2’s role within Parkinson’s disease, Huntington’s disease, and ischemic stroke in preclinical mouse models and humans with age-related neurodegenerative diseases.”

https://www.sciencedirect.com/science/article/pii/S1568163722001982 “Role of Nrf2 in aging, Alzheimer’s and other neurodegenerative diseases” (not freely available) Thanks to Dr. P. Hemachandra Reddy for providing a copy.

One of the Part 3 study’s coauthors contributed to this very detailed review:

“Due to observed overlapping cellular responses upon AMPK or NRF2 activation and common stressors impinging on both AMPK and NRF2 signaling, it is plausible to assume that AMPK and NRF2 signaling may interdepend and cooperate to readjust cellular homeostasis.

1-s2.0-S089158492200497X-gr3_lrg

The outcome and underlying signaling events of AMPK-NRF2 crosstalk may diverge between:

  1. in vitro and in vivo studies (one cell type in isolation vs inter-organ crosstalk in living organisms);
  2. Different cell types/organs/organisms of different cultivation conditions, genetic background, age or sex;
  3. Different stress-regimens (chronic vs acute, nature of stress (lipotoxicity, redox stress, xenobiotic, starvation, etc));
  4. Different modes of Nrf2 or AMPK activation and inhibition (genetic vs pharmacological, constitutive vs transient/intermittent, systemic vs organ-specific, electrophilic vs PPI, allosteric vs covalent, or pan vs subtype-specific);
  5. Different target genes with distinct promoter and enhancer structure; or
  6. Different timing of activation.

The latter should deserve increased attention as Nrf2 is one of the most cycling genes under control of the circadian clock. Feeding behavior, metabolism and hence AMPK activity follow and substantiate the biological clock, indicating an entangled circadian regulation of metabolic and redox homeostasis.”

https://www.sciencedirect.com/science/article/pii/S089158492200497X “AMPK and NRF2: Interactive players in the same team for cellular homeostasis?”

A third citing paper was a study of lens cells that provided an example of similar metformin effects noted in Part 2 of Broccoli sprouts activate the AMPK pathway:

“Loss of Nrf2 and Nrf2 antioxidant genes expression and activity in aging cells leads to an array of oxidative-induced deleterious responses, impaired function, and aging pathologies. This deterioration is proposed to be the primary risk factor for age-related diseases such as cataracts.

AMPK regulates energy at physiological levels during metabolic imbalance and stress. AMPK is a redox sensing molecule, and can be activated under cellular accumulation of reactive oxygen species, which are endogenously produced due to loss of antioxidant enzymes.

The therapeutic potential of AMPK activation has context-dependent beneficial effects, from cell survival to cell death. AMPK activation was a requisite for Bmal1/Nrf2-antioxidants-mediated defense, as pharmacologically inactivating AMPK impeded metformin’s effect.

Using lens epithelial cell lines (LECs) of human or mouse aging primary LECs along with lenses as model systems, we demonstrated that metformin could correct deteriorated Bmal1/Nrf2/ARE pathway by reviving AMPK-activation and transcriptional activities of Bmal1/Nrf2, resulting in increased antioxidants enzymatic activity and expression of Phase II enzymes. Results uncovered crosstalk between AMPK and Bmal1/Nrf2/antioxidants mediated by metformin for blunting oxidative/aging-linked pathobiology.”

https://www.mdpi.com/2073-4409/11/19/3021/htm “Obligatory Role of AMPK Activation and Antioxidant Defense Pathway in the Regulatory Effects of Metformin on Cellular Protection and Prevention of Lens Opacity”

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If you were given a lens to see clearly, would you accept it?

gettingwell4 4-5 stars Advanced knowledge, Amygdala, Brainstem, Cerebrum, Cortisol, Epigenetics, Hippocampus, Hypothalamus, Limbic system, Locus coeruleus, Lower brain, Memory, Neurochemicals, Primal Therapy, Serotonin, Stress , , , , , , , ,

Two papers, starting with a 2022 rodent study of maternal behaviors’ effects on offspring physiologies:

“Early life adversity (ELA) is a major risk factor for development of pathology. Predictability of parental care may be a distinguishing feature of different forms of ELA.

We tested the hypothesis that changes in maternal behavior in mice would be contingent on the type of ELA experienced, directly comparing predictability of care in the limited bedding and nesting (LBN) and maternal separation (MS) paradigms. We then tested whether predictability of the ELA environment altered expression of corticotropin-releasing hormone (Crh), a sexually-dimorphic neuropeptide that regulates threat-related learning.

MS was associated with increased expression of Crh-related genes in males, but not females. LBN primarily increased expression of these genes in females, but not males.”

https://www.sciencedirect.com/science/article/pii/S2352289522000595 “Resource scarcity but not maternal separation provokes unpredictable maternal care sequences in mice and both upregulate Crh-associated gene expression in the amygdala”

I came across this first study by it citing a republished version of 2005 epigenetic research from McGill University:

“Early experience permanently alters behavior and physiology. A critical question concerns the mechanism of these environmental programming effects.

We propose that epigenomic changes serve as an intermediate process that imprints dynamic environmental experiences on the fixed genome resulting in stable alterations in phenotype. These findings demonstrate that structural modifications of DNA can be established through environmental programming and that, in spite of the inherent stability of this epigenomic marker, it is dynamic and potentially reversible.”

https://www.tandfonline.com/doi/full/10.31887/DCNS.2005.7.2/mmeaney “Environmental programming of stress responses through DNA methylation: life at the interface between a dynamic environment and a fixed genome”

This post commemorates the five-year anniversary of Dr. Arthur Janov’s death. Its title is taken from my reaction to his comment on Beyond Belief: Symptoms of hopelessness. Search his blog for mentions of the second paper’s coauthors, Drs. Meaney and Szyf.

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All about walnuts’ effects

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Five 2022 papers focusing on walnuts, starting with a comparison of eight tree nuts:

“The aim of the present study was to examine 8 different popular nuts – pecan, pine, hazelnuts, pistachio, almonds, cashew, walnuts, and macadamia. Total content of phenolic compounds in nuts ranged from 5.9 (pistachio) to 432.9 (walnuts) mg/100 g.

Walnuts had the highest content of polymeric procyanidins, which are of great interest as important compounds in nutrition and biological activity, as they exhibit antioxidant, anti-inflammatory, antimicrobial, cardio- and neuroprotective action. Walnuts are good sources of fatty acids, especially omega-3 and omega-6.”

https://www.sciencedirect.com/science/article/pii/S2590157522002164 “Nuts as functional foods: Variation of nutritional and phytochemical profiles and their in vitro bioactive properties”

A second study compared the same eight tree nuts plus Brazil nuts and peanuts:

“The highest total content of all analyzed flavonoids was determined in walnuts (114.861 µg/g) with epicatechin the most abundant, while the lowest was in almonds (1.717 µg/g). Epicatechin has antioxidant, anti-inflammatory, antitumor, and anti-diabetic properties. Epicatechin has beneficial effects on the nervous system, enhances muscle performance, and improves cardiac function.”

https://www.mdpi.com/1420-3049/27/14/4326/htm “The Content of Phenolic Compounds and Mineral Elements in Edible Nuts”

Next, two systematic reviews and meta-analyses of human studies:

“We carried out a systematic review of cohort studies and randomized controlled trials (RCTs) investigating walnut consumption, compared with no or lower walnut consumption, including those with subjects from within the general population and those with existing health conditions, published from 2017 to 5 May 2021.

  • Evidence published since 2017 is consistent with previous research suggesting that walnut consumption improves lipid profiles and is associated with reduced CVD risk.
  • Evidence pointing to effects on blood pressure, inflammation, hemostatic markers, and glucose metabolism remains conflicting.
  • Evidence from human studies showing that walnut consumption may benefit cognitive health, which is needed to corroborate findings from animal studies, is now beginning to accumulate.”

https://academic.oup.com/nutritionreviews/advance-article/doi/10.1093/nutrit/nuac040/6651942 “Walnut consumption and health outcomes with public health relevance – a systematic review of cohort studies and randomized controlled trials published from 2017 to present”

“We aimed to perform a systematic review and meta-analysis of RCTs to thoroughly assess data concerning effects of walnut intake on selected markers of inflammation and metabolic syndrome in mature adults. Our findings showed that:

  • Walnut-enriched diets significantly decreased TG, TC, and LDL-C concentrations, while HDL-C levels were not significantly affected.
  • No significant changes were noticed on anthropometric, cardiometabolic, and glycemic indices after higher walnut consumption.
  • Inflammatory biomarkers did not record statistically significant results.”

https://www.mdpi.com/2076-3921/11/7/1412/htm “Walnut Intake Interventions Targeting Biomarkers of Metabolic Syndrome and Inflammation in Middle-Aged and Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials”

Finishing with a rodent study that gave subjects diabetes with a high-fat diet, then mixed two concentrations of walnut extract in with the treatment groups’ chow:

“This study was conducted to evaluate the protective effect of Gimcheon 1ho cultivar walnut (GC) on cerebral disorder by insulin resistance, oxidative stress, and inflammation in HFD-induced diabetic disorder mice. After HFD feed was supplied for 12 weeks, samples were orally ingested for 4 weeks to GC20 and GC50 groups (20 and 50 mg/kg of body weight, respectively).

  • Administration of GC improved mitochondrial membrane potential function, and suppressed oxidative stress in the brain.
  • GC inhibited hepatic and cerebral lipid peroxidation and the formation of serum AGEs, and increased serum antioxidant activity to improve HFD-induced oxidative stress.
  • The HFD group showed significant memory impairment in behavioral tests. On the other hand, administration of GC showed improvement in spatial learning and memory function.

walnut brain effects

Based on these physiological activities, GC showed protective effects against HFD-induced diabetic dysfunctions through complex and diverse pathways.”

https://www.mdpi.com/1420-3049/27/16/5316/htm “Walnut Prevents Cognitive Impairment by Regulating the Synaptic and Mitochondrial Dysfunction via JNK Signaling and Apoptosis Pathway in High-Fat Diet-Induced C57BL/6 Mice”

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Minds of their own

gettingwell4 5+ stars Premium, Brain development, Brain hemispheres, Epigenetics, Memory, Neurochemicals, Serotonin, Stress , , , , , ,

It’s the weekend, so it’s time for: Running errands? Watching sports? Other conditioned behavior?

Or maybe broadening our cognitive ability with Dr. Michael Levin’s follow-ups to his 2021 Basal cognition paper and 2020 Electroceuticals presentation with a 2022 paper and presentation starting around the 13:30 mark:

Michael Levin - Cell Intelligence in Physiological and Morphological Spaces

“A homeostatic feedback is usually thought of as a single variable such as temperature or pH. The set point has been found to be a large-scale geometry, a descriptor of a complex data structure.”

His 2022 paper Technological Approach to Mind Everywhere: An Experimentally-Grounded Framework for Understanding Diverse Bodies and Minds:

“It is proposed that the traditional problem-solving behavior we see in standard animals in 3D space is just a variant of evolutionarily more ancient capacity to solve problems in metabolic, physiological, transcriptional, and morphogenetic spaces (as one possible sequential timeline along which evolution pivoted some of the same strategies to solve problems in new spaces).

Developmental bioelectricity works alongside other modalities such as gene-regulatory networks, biomechanics, and biochemical systems. Developmental bioelectricity provides a bridge between the early problem-solving of body anatomy and the more recent complexity of behavioral sophistication via brains.

This unification of two disciplines suggests a number of hypotheses about the evolutionary path that pivoted morphogenetic control mechanisms into cognitive capacities of behavior, and sheds light on how Selves arise and expand.

While being very careful with powerful advances, it must also be kept in mind that existing balance was not achieved by optimizing happiness or any other quality commensurate with modern values. It is the result of dynamical systems properties shaped by meanderings of the evolutionary process and the harsh process of selection for survival capacity.”

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