Flavonoids May Modulate BDNF and Amyloid In Alzheimer's ~!

"stimulating BDNF and reducing Aβ toxicity by natural flavonols provide a therapeutic implication for treatment of AD."


Hou, Y. et al. Anti-depressant natural flavonols modulate BDNF and beta amyloid in neurons and hippocampus of double TgAD mice. Neuropharmacology 58, 911-920 (2010). URL http://dx.doi.org/10.1016/j.neuropharm.2009.11.002.


Related:
Health and Environmental Illness Blog: Solvents, PAHs and BDNF as a Modulator of TrkB, Anxiety and Nrf2~!

Nrf2's Regulation of NRF1 and Its Influence on NMDA Subunits and Environmental Illness - see comments.

Dynamic Changes in Brain Occur With Sleep Deprivation that Include NRF1, NRF2

"There are complex dynamic changes in brain energy regulation with extended wakefulness"

Read more: SLEEP - Article Abstract:

Role of CO in cardiac mitochondrial biogenesis

"Mitochondrial biogenesis is activated by gene and protein expression of the nuclear respiratory factor 1 (NRF1) and NRF2, of peroxisome proliferator-activated receptor gamma co-activator-1, and of mitochondrial transcription factor A (TFAM), which augmented the copy number of mitochondrial DNA (mtDNA). This is independent of nitric oxide synthase (NOS), as demonstrated by the identical responses in wild-type and endothelial NOS (eNOS)-deficient mice, and by the inhibition of inducible NOS (iNOS)."

A new activating role for CO in cardiac mitochondrial biogenesis -- Suliman et al. 120 (2): 299 -- Journal of Cell Science:

Parkinson's and Link To Muscle Protein and Cell Signaling Pathway?

I recently noted that transcription factors such as MEF2, NRF1, NRF2 are co-activated by PGC-1a (important for mitochondrial biogenesis) results in kind of a loop to increase the expression of PGC-1a. PGC-1a regulates a number of transporters that regulate chemicals across membranes and alterations in these proteins may increase or lead to tissue dysfunction.

Recent evidence indicates that chaperone-mediated autophagy plays a role in direct degradation of neuronal transcription factor MEF2D, a protein known to promote neuronal survival. Disruption of this regulatory pathway by α-synuclein leads to neuronal stress, which may underlie neuronal loss in Parkinson’s disease.

For further reading:

• Nrf2's Regulation of NRF1 and Its Influence on NMDA Subunits and Environmental Illness
• Altered Metabolism, Toxicity, Glutamate Dehydrogenase and NRF-1 and Its Activator PGC-1
• Heme Oxygenase-1 Regulates Cardiac Mitochondrial Biogenesis via Nrf2-Mediated Transcriptional Control of Nuclear Respiratory Factor-1 -- Piantadosi et al. 103 (11): 1232 Figure IG7 -- Circulation Research
• Impairments in Muscle Function After Cigarette Exposure and Environmental Illness

Yang, Q. and Mao, Z. (2010). Dysregulation of autophagy and parkinson's disease: the mef2d link. Apoptosis. http://www.citeulike.org/user/HEIRS/article/6715832
Wright, D. C., Han, D.-H. H., Garcia-Roves, P. M., Geiger, P. C., Jones, T. E., and Holloszy, J. O. (2007). Exercise-induced mitochondrial biogenesis begins before the increase in muscle pgc-1alpha expression. The Journal of biological chemistry, 282(1):194-199. http://www.citeulike.org/user/HEIRS/article/6580001
Brockmann, K., Wang, D., Korenke, C. G., Von Moers, A., Ho, Y.-Y., Pascual, J. M., Kuang, K., Yang, H., Ma, L., Kranz-Eble, P., Fischbarg, J., Hanefeld, F., and De Vivo, D. C. (2001). Autosomal dominant glut-1 deficiency syndrome and familial epilepsy. Annals of Neurology, 50(4):476-485. http://www.citeulike.org/user/HEIRS/article/6715941
Hernandez, M. J., Roberts, T. M., and Hardin, C. D. (2007). Caveolin-1 and the organization of glycolysis in astrocytes: Modulation by ammonia. The FASEB Journal, 21. http://www.citeulike.org/user/HEIRS/article/6715979
Klinge, C. M. (2008). Estrogenic control of mitochondrial function and biogenesis. Journal of Cellular Biochemistry, 105(6):1342-1351. http://www.citeulike.org/user/HEIRS/article/3879108

Nrf2's Regulation of NRF1 and Its Influence on NMDA Subunits and Environmental Illness

As we have noted the Nrf2 regulates a number of genes including those that are important for mitochondrial biogenesis and other homeostatic functions and the expression of it can be effected by age, injury, oxidative stress, nutrition and other behavioral factors. As Dhar shows, the NRF-1 transcription factor upregulated by Nrf2 and important for PGC-1a activation and mitochondrial biogenesis has been shown to co-regulate a number of different genes including that for NR1, NR2b and Cox1. The Nr2b is a subunit of the NMDA which has been implicated in nociception of MCS upon upregulation (Pall) as well as, has been implicated in having involvement in other environmental illnesses including fibromyalgia. Its involvement also provides important implications for conditions of learning and cognitive difficulties that usually are co-morbid with these conditions. There does seem to be some debate on whether NMDA is upregulated or down-regulated and it may be that specific situations influence this. Yonden previously demonstrated that the downregulation of the NR2b receptor occurs with addition of experimental ammonia and concluded that downregulation of the NMDA contributes to severity of hepatic encephalopathy. This also supports our opinion that Nrf2 may influence environmental conditions including MCS and others because it is important for regulation of NRF1. It also provides supporting evidence that other health conditions where mitochondrial dysfunction is a factor, may also be influenced by the expression of Nrf2 because NRF1's role in mitochondrial biogenesis.

HEIRS Tags: NR2B, NRF1, hyperammonia,
For Further Reading: Nrf2, Ornithine Transferase, Autism and Maternal Age -- A Possible Link?

CiteULike: Coupling of Energy Metabolism and Synaptic Transmission at the Transcriptional Level: Role of Nuclear Respiratory Factor 1 in Regulating both Cytochrome c Oxidase and NMDA Glutamate Receptor Subunit Genes: "Dhar, S. S. and Wong-Riley, M. T. T. (2009). Coupling of energy metabolism and synaptic transmission at the transcriptional level: Role of nuclear respiratory factor 1 in regulating both cytochrome c oxidase and nmda glutamate receptor subunit genes. J. Neurosci., 29(2):483-492."
Yonden, Z., Aydin, M., Kilbas, A., Demirin, H., Sutcu, R., and Delibas, N. (2010). Effects of ammonia and allopurinol on rat hippocampal nmda receptors. Cell biochemistry and function. http://www.citeulike.org/user/HEIRS/article/6567065
Pall, Martin.  (2007). Explaining Ünexplained Illnesses": disease paradigm for chronic fatigue syndrome, multiple chemical sensitivity, fibromyalgia, post-traumatic syndrome, Gulf War syndrome, and others. Harrington Park Press:Hawthorne Press, 10 Alice Street Binghampton NY 13904. http://www.citeulike.org/user/HEIRS/article/3042479

Study shows correlation between mitochondrial biogenesis and G6PDH

Recent study shows correlation between G6PDH and mtDNA replication. This
may account for low developmental competance in these animals. Marker changes
include those for COX1, NRF1 and tFAM.

CiteULike: Transcript expression of mitochondria related genes is correlated with bovine oocyte selection by BCB test.: "Opiela, J., Lipiński, D., Słomski, R., and Katska-Ksiazkiewicz, L. (2010). Transcript expression of mitochondria related genes is correlated with bovine oocyte selection by bcb test. Animal reproduction science, 118(2-4):188-193."

Promoters & Inhibitors of the Metabolic & Antioxidative Pathway of PGC-1a and Its Role in Environmental Illness

When you are talking about biological pathways there is never a linear path where one protein action only leads to another. It would make understanding these pathways alot simpler but it just does not work that way. Of course, if this were so, it would be so easy for everything to just stop working if something went wrong. When there are multiple pathways that intersect, run parallel or make feedback loops on proteins that ultimately activate other proteins, it results in a kind of "checks and balance system" inside a cell. This provides a safety mechanism so processes keep working or at least "keep chugging along" even if one protein or even a few proteins that make up a pathway are damaged, are lost or their signals get misdirected. It is easy to get confused when thinking about all those protein interactions at the same time. For me.... it is easier to break the activities down and focus on the processes individually. It makes it easier to understand how these pathways work and easier to remember just what they do! (If you would like to see a graphical depiction of the tangled mess these pathways make - click here!) Today's focus is on mostly on the PGC1a pathway and its relevance to the molecular biology of environmental illnesses.

In a recent blog, I wrote about my interest in nutrition as well as, a variety of other topics I have studied that impact health and wellness. In that blog, I discussed how a number of dietary excesses or deficiencies may influence environmental disease. Specifically dietary deficiencies include vitamin D, vitamin B and folate and also may include methionine(either too little or too much). I added changes in human dietary patterns and lifestyles over the last several decades or more may have contributed to this. There is debate on whether we get too much or too little methionine from our diet. The most recent articles provide evidence that methionine actually increases mitochondrial stress and lack of DNA repair even though others recommend supplementation of methionine. Generally, our bodies use methionine to make something called s-adenosyl methionine (SAM) which is used for biosynthesis of hormones like dopamine and serotonin. (Deth, Cully) It breaks down into homocysteine which can be toxic at excess amounts but with the help of B6, B12 and folate it recycles back into methionine or glutathione. (This means we have to have substantial amounts of these nutrients too!) Methionine can also be used to make cysteine, cartinine, taurine and lecithin. Excess levels of homocysteine (homocysteinemia) has been demonstrated to have negative effects on the cardiovascular system, impair the urea cycle and may produce problematic cognitive effects. It has recently been demonstrated that PGC-1a effects homocysteine metabolism and overexpression of the antioxidant may elevate levels of homocysteine and lower PGC-1a expression is associated with lower plasma homocysteine levels. Low levels of homocysteine can alter the normal metabolism of glutathione, taurine and sulfate and therefore can be a health concern. Because homocysteine is the intermediate in the production of methionine to cysteine, it may make one more susceptible to oxidative stress and certain toxic exposures. In these cases, NAC, methionine and taurine are often recommended.

Now that we have reviewed how PGC-1a interacts with the methionine synthase pathway, let us now discuss more about this protein and its importance for maintaining overall cellular metabolism and homestasis. Homeostasis inside cells can be severely impaired without proper expression of PGC-1a because its expression influences the regulation of a number of other proteins including the PPARS, estrogen, thyroid hormone, glucocorticoids and the pregnane X receptor, just to name a few. (Finck) To demonstrate this take for example how the pregnane X receptor interacts with PGC-1a in the synthesis of CYPA26 and CYPA34. These are two enzymes necessary for the metabolism and/or detoxification of certain anesthetics, antidepressants, nicotine and other contaminants like certain molds. Additional key targets for PGC-1a include NRF1 and NRF2 which regulate mitochondrial function. The former, NRF1, is regulated by Nrf2 and taken together, Nrf2 and PGC-1a are responsible for most of the activities that promote oxidative stress resistance and cellular survival in toxic environments. PGC-1a also interacts with vitamin D and "because the expression of PGC-1α is regulated by environmental stimuli, such as diet and lower temperatures, it follows that the function of VDR could be influenced in response to these external stimuli in the tissues that exhibit an overlap in the expression of PGC-1α." (Savkur)

The PGC-1a gene responds to a number of different environmental cues including diet like fasting, caffeine, exercise and cold exposure and is preferentially expressed in tissues with high oxidative capacity. (Finck) On the other hand, it is inhibited by obesity, lack of exercise and the exposure to endotoxin. These factors lead one to consider important policy and regulatory concerns for the elderly and vulnerable populations, those with access issues to proper nutrition or individuals living with unhospitable conditions like contaminated water supplies. In general, the inhibition of PGC-1a expression has a variety of physiological effects including lower cardiac function, lower mitochondrial function, endothelial and epithelial dysfunction, poor thermoregulation, lower protection against environmental toxins, reduced energy metabolism, alterations of muscle fiber type and numerous others. One will note, all of these contribute to a variety of complications indentified in patients with environmental illnesses. As Patti describes, one complication from reduced PGC-1a expression leading to oxidative stress and altered cellular metabolism is insulin resistance and diabetes. As we noted earlier, PGC-1a interacts with NRF-1 a nuclear respiratory factor. This author demonstrates that although NRF-1 is reduced in diabetics, a number of other proteins that interact with and including PGC-1a such as PGC-1b, PPAR-gamma and NRF1 are also reduced in members of their families. From this it is assumed that decreased expression of PGC-1a is responsible for a decrease in NRF genes and the associated disturbances of insulin resistance and diabetes.

At this point, it would be worth suggesting here that metabolic disturbances may not only be the result of a reduction in expression in PGC-1a but may also be due to a reduction in the expression or regulation of NRF1 by Nrf2 at least in some cell types. One protein that has been implicated in a number of mental and physical health disorders, GSK-3b, is like an off and on switch for the Nrf2 antioxidant system that allows for cellular stress resistance. Also, other proteins may participate and PGC-1a inhibition. Tnf-a from cigarette smoke inhibites PGC-1a and may be a "key step" to vascular and myocyte dysfunction. (Tang) Both NRF1 and NRF2 are involved in the generation of the respiratory chain and it seems NRF1's role includes inducing gene expression and maintaining cytochrome C levels. An interesting article explains that several pathways exist that inhibit PGC-1a which may be different in different tissues. In addition to possible inhibition of PGC-1a in hepatocytes by Akt/PKB, there is evidence expression of PGC-1a can be dependant on reduction of a ligase called Cdc4 or through the activation of GSK-3b which also contributes to neuroinflammation. GSK-3b increases in response to oxidative stress and can regulate the TH1/Th2 balance (Ohtani) and its inhibition according to one author may lead to "stabilization of PGC-1a". Cdc4 is elevated in Parkinson's disease and as one author mentions, "it will be interesting to see if Cdc4 is responsible for the reduction of PGC-1a in the brains of PD patients." (Olson) For GSK-3b, metallothionein which can be upregulated by Nrf2 is an effective inhibitor of GSK-3b and prevents a number of diabetic-induced changes in inflammation, nitrosative stress and energy metabolism. (Wang) In cardiac cells the presense of metallothionein "abrogates mitochondrial damage, loss of mitochondrial DNA and downregulation of PGC-1a and its downstream targets. In this article the author proposes eNOS uncoupling induces the down-regulation of PGC-1a, NRF1, NRF2 and other proteins which contributes to the loss of mitochondrial biogenesis while saying further the precise mechanism for loss of mitochondrial biogenesis under eNOS uncoupling is not known. It might be important to stress here that it is now understood that Nrf2 is an important protective component against eNOS uncoupling. (Heiss) Recent evidence provides evidence of an alternative mechanism involving elevations in CO and H2O2 activates mitochondrial biogenesis through PGC-1a independantly of eNOS. In any event, PGC-1a expression is vital for normal heart function, because reductions in expression of PGC-1a results in compromised function. Other important inducers of PGC-1a include cAMP, CAMKII, AMPK and NO.

Numerous studies demonstrate and as we mentioned earlier, exercise elevates both PGC-1a gene and protein expression. As Wright explains, "with this discovery it was initially believed that exercise-induced biogenesis was mediated by increases in PGC-1a but suggests that activation of PGC-1a mediates mitochondrial biogenesis rather than the increases in protein expression." His study provides support for this because a) PGC-1a regulates binding of NRF1 and NRF2 and he demonstrates that their binding increased after exercise but before there was an increase in PGC-1a protein expression and b) a number of mitochondrial constituents were increased beforeelevations in protein levels. Other studies have demostrated that P38 activation is linked to an adaptive increase in mitochondrial biogenesis. Wright agrees and believes that generally PGC-1a production occurs in this order 1) exercise activates P38 which in turn activates PGC-1a 2) PGC-1a activates transciption factors and nuclear receptors that regulate mitochondrial expression which is part of the first phase of an adaptive response, 3) activation of the PGC-1a by the promoter and transcription factors coactivated by PGC-1a results in an increase in PGC-1a expression and 4) this mediates the second phase of an adaptive response and includes sustaining and enhancing mitochondrial biogenesis by PGC-1a. With all this in mind, one must consider that mitochondrial biogenesis and homostastic metabolism is dependant at least in part on participation of Nrf2 antioxidant system because it also regulates NRF1 and therefore, impairments of this system may contribute to conditions in metabolism where PGC-1a plays a central role.

Notes:

• Lipoic acid increases mitochondrial biogenesis and improves muscular energy through a AMPK-PGC-1a pathway which increases GLUT4 expression in aged mice. (Wang)

Original document and citations.

Impairments in Muscle Function After Cigarette Exposure and Environmental Illness

PGC-1a a protein factor necessary for mitochondrial function and may be reduced with exposure to LPS as well as, from impairments in Nrf2. This study demonstrates that TNF-a (already identified as a factor in CFS and Parkinson's) is generated from exposure to cigarette smoke (and lots of other environmental contaminants) and has been shown to down-regulate PGC-1a that may lead to vascular and myocyte dysfunction. PGC-1a also regulates a number of glucose transporters such as GLUT1 and GLUT4 which trasport glucose into cells.  When one looks at a condition related to glucose uptake from impairment of glucose transporters such as in GLUT1 deficiency, there are recognizable patterns of impairment one may recognize in other environmental illnesses including CFS and fibromyalgia and also described as Parkinsonism and ataxia-like symptoms.  Because Nrf2 contributes to PGC-1a expression, a deficiency in Nrf2 may also present with these types of symptoms impaired after cigarette exposure and particulate matter from diesel exhaust. Of course, other factors such as accumulation of ammonia and genetic SNP may also pose potential cellular threats. PGC-1a can be increased through exercise but this will be dependant on the availabity of NRF1 (another protein) regulated by Nrf2/HO-1. Sauna and Waon therapy have been shown to elevate PGC-1a and Nrf2. Deficiencies of PGC-1a may exacerbate the autoimmune-type presentation of environmental illness in Nrf2 deficiencies which produce less HO-1. Lack of PGC-1a and Nrf2 may contribute to the development of chronic diabetes in addition to other metabolic complications and numerous other conditions, such as cardiovascular disease.


For review:

• Chemical Sensitivity and Th2 Autoimmune Disease: The Loss of Treg Cells As Referee!
• Immunosuppression in Environmental Illness By High Fat and Cytokines: Ameliorated By Green Tea Compound!?
• Nrf2 Expression Is Regulated by Epigenetic Mechanisms in Prostate Cancer
• T Regulatory Cells and Vitamin D - Their Importance to Environmental Illness Including Chemical Sensitivity.

CiteULike: TNF-alpha-mediated reduction in PGC-1alpha may impair skeletal muscle function after cigarette smoke exposure.: "Tang, K., Wagner, P. D., and Breen, E. C. (2010). Tnf-alpha-mediated reduction in pgc-1alpha may impair skeletal muscle function after cigarette smoke exposure. Journal of cellular physiology, 222(2):320-327."





Lihua CHE, N. and Chiwai WON, G. Estrogen-related receptor a inverse agonist enhances basal glucose uptake in myotubes through reactive oxygen species. Biological Pharmacology Bulletin, 32(7):1199-1203. http://www.citeulike.org/user/HEIRS/article/6512026
Arany, Z., Foo, S.-Y. Y., Ma, Y., Ruas, J. L., Bommi-Reddy, A., Girnun, G., Cooper, M., Laznik, D., Chinsomboon, J., Rangwala, S. M., Baek, K. H. H., Rosenzweig, A., and Spiegelman, B. M. (2008). Hif-independent regulation of vegf and angiogenesis by the transcriptional coactivator pgc-1alpha. Nature, 451(7181):1008-1012. http://www.citeulike.org/user/HEIRS/article/2406298
Pons, R., Collins, A., Rotstein, M., Engelstad, K., and De Vivo, D. C. (2009). The spectrum of movement disorders in glut-1 deficiency. Movement Disorders, 9999(9999):NA+. http://www.citeulike.org/user/HEIRS/article/6512017
Piantadosi, C. A., Carraway, M. S., Babiker, A., and Suliman, H. B. (2008). Heme oxygenase-1 regulates cardiac mitochondrial biogenesis via nrf2-mediated transcriptional control of nuclear respiratory factor-1. Circ Res, 103(11):1232-1240. http://www.citeulike.org/user/HEIRS/article/4617070?show_msg=already_posted
Glucose Transporter. Wipedia. Retrieved January 10, 2009.