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Searching for a TDP-43 therapy

Genetic therapies against TDP-43 aggregates had been proposed for ALS disease.

While this is certainly feasible with the current state of art (see my book), it would certainly be sold at a cost similar to Zolgensma, because of the lack of competition in the field.

The classical drug which complies with the "Pfizer rule of five" is a peptide, so a peptide that would remove TDP-43 would be desirable. Peptides are low cost and easy to procure.

Improving an already published peptide

Several scientific articles [0] are suggesting that a peptide might help in ALS by removing TDP-43 from mitochondria.

YGRKKRRQRRRAQFPGACGL

While a patent was written in 2016 (and still valid for 2019) the main scientist lost faith in it as it is very toxic.

The proposed peptide is formed by assembling a M1 section from TDP-43 with a TAT peptide.
* The M1 section is: FPGACGL
* The M3 section is: GFGFV
* Tat is a regulatory protein that drastically enhances the efficiency of viral transcription, for example in HIV with a transition to the most dangerous form of AIDS (T-tropic).

Bioinformatics tools suggest that its biological function as a neurotoxin which blocks acetylcholine receptors.

An improved peptide

If we use a peptide made simply with the M1 section followed by the M3 section.

This peptide, FPGACGLGFGFV, is predicted by bioinformatics tools has not being a toxin, and not an antigen.

Therefore it seems safe (but more tests are needed), while retaining the two sections that are told as helping in removing the TDP-43 from mitochondria.

However a Blast test shows it is very close to other human proteins so it certainly have side effects. It should also be designed to able to traverse the blood-brain barrier, as well as entering cells.

Conclusion: While a lot of work is still necessary to design a peptide without side effects, some interesting results have already being achieved: A peptide with a design similar to peptides able to remove TDP-43 from mitochondriais designed. This peptide is probably not toxic, but probably with side effects. Its effectiveness to traverse the BBB was not tested with bioinformatic tools.

Tool for testing neurotoxin function:
https://webs.iiitd.edu.in/raghava/ntxpred
Tool for testing immunogenicity:
http://www.ddg-pharmfac.net/vaxijen/
Blast on human genome:
https://blast.ncbi.nlm.nih.gov/Blast.cgi

[0] Including: The Inhibition of TDP-43 Mitochondrial Localization Blocks Its Neuronal Toxicity Article in Nature medicine · June 2016 DOI: 10.1038/nm.4130

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This book retraces the main achievements of ALS research over the last 30 years, presents the drugs under clinical trial, as well as ongoing research on future treatments likely to be able stop the disease in a few years and to provide a complete cure in a decade or two.

There is many questions about how TDP-43 can be deleterious in ALS disease. Normally TDP-43 is involved in many repairing or protecting scenarios. In 2013 scientists proposed that misplaced TDP-43 was killing mitochondria, by disturbing their fission/fusion processes (mitochondria are very dynamic structures). However this is not the scientific consensus.

A scientific article published on October 30, 2019 about Alzheimer's disease confirms the effect of a peptide against the aggregation of TDP-4 in mitochondria. This peptide and others were already described in a 2016 ALS publication.

The molecular mechanisms by which TDP-43 contributes to the pathology of ALS remained elusive. In the 2016 article, the authors wrote that they found that TDP-43 accumulated in neuronal mitochondria in subjects with ALS or frontotemporal dementia. Neurodegenerative diseases are characterized by cytoplasmic localization of TDP-43 in granule types. The 2016 study directly linked the toxicity of TDP-43 to mitochondrial metabolism and proposed targeting the mitochondrial localization of TDP-43 as a promising therapeutic approach for ALS.

The authors of the 2019 study (Gao et al.), They, demonstrate that one of the two mitochondrial TDP-43 inhibitory peptides of the 2016 article, when administered late in the course of the disease, may attenuate the development and progression of cerebral neuronal loss and behavioral deficits in the 5XFAD transgenic mouse model in Alzheimer's disease.

If this peptide is effective against TDP-43 proteininopathies, it is a real breakthrough because a peptide is something that is easy to produce at a low cost.

In neurodegenerative diseases, TDP-43 is localized in the cytoplasm as well as in mitochondria that may be free in the cytoplasm or anchored in the endoplasmic reticulum, where it gives it the "raw" appearance of the endoplasmic reticulum.

TDP-43 or truncated forms of TDP-43 may be present inside or outside the mitochondria. The portion of the total length of TDP-43 within the mitochondria can bind to the subunits encoding the mitochondria-mediated messenger RNA (mRNA), whereas the truncated TDP-43 lacks the locating sequence. mitochondrial M1 is limited to the inner membrane space no effect on ND3 / 6 expression or mitochondrial function.

The mitochondrial localization of TDP-43 is dependent on its M1 motif, the deletion of which suppresses its mitochondrial accumulation with no significant effect on its half-life, dimerization, functional binding to mRNA targets and cytosolic TDP-43 expression. , nuclear or total. The PM1 synthesized peptide (YGRKKRRQRRRAQFPGACGL) in which the M1 motif was fused to the TAT peptide (GRKKRRQRRR), competitively inhibits the mitochondrial localization of TDP-43 and suppresses the TDP-43 induced toxicity on mitochondria and non-influencing neurons. on TDP-43 expression neurons

The authors used PM1, a peptidic inhibitor derived from TDP-43, as a continuous injection, to specifically reduce its expression in mitochondria. PM1 abolished TDP-43 protein kinetics, reversed neuronal loss, and reduced neuroinflammation in aged 5XFAD mice long after symptom onset. Since the amyloid plaque load was not attenuated or prevented by PM1, the authors' results clearly indicate that TDP-43 in mitochondria does not affect the pathology of Aβ.

Chronic administration of the PM1 peptide significantly attenuated TDP-43 protein kinetics, mitochondrial abnormalities, microgliosis, and even neuronal loss, but was without effect on amyloid plaque load in 12-month-old 5XFAD mice well after the onset of symptoms. PM1 also improved cognitive and motor functions in 12-month-old 5XFAD mice and completely prevented the development of mild cognitive impairment in 6-month-old 5XFAD mice.

Beyond its involvement in Alzheimer's disease, this article corroborates the 2016 article on ALS and therefore offers hope that a continuous (insulin pump-like) delivery of a low-cost peptide could to be very beneficial for ALS.

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This book retraces the main achievements of ALS research over the last 30 years, presents the drugs under clinical trial, as well as ongoing research on future treatments likely to be able stop the disease in a few years and to provide a complete cure in a decade or two.

The end of the amyloid plaque hypothesis for Alzheimer's disease

Nearly two decades have passed since an Alzheimer's drug was approved. This, too, is reminiscent of the situation of ALS.

Researchers working on Alzheimer's disease, have broadened their approaches after years devoted to the so-called amyloid hypothesis, which tells that the accumulation of a protein called beta-amyloid in brain plaques is at the origin of the disease. Indeed the tests of drugs that had to eliminate these plaques, have all regularly failed in patients. A similar situation is true also in ALS and also for other neurodegenerative diseases. Maybe our basic concepts about these diseases are wrong.

In October 2019, however, Biogen announced that it would seek approval by the Food and Drug Administration for an anti-amyloid drug called aducanumab, which had failed in two previous trials. The company said a new analysis of some of the trial's data had shown a reduction in cognitive decline in some patients with early Alzheimer's disease.

The intestinal microbiota

The gut microbiota changes before the onset of Alzheimer's disease and these alterations can be detected earlier at the stage of mild cognitive impairment. There is a certain relationship between amyloid plaques and certain microbes. Several bacterial species, including Bacillus subtilis, E. coli, Mycobacterium tuberculosis, Salmonella enterica, Salmonella typhimurium and Staphylococcus aureus, are capable of producing amyloid fibers. Everything goes as if instead of being a perfect body, in accordance with school books, the aging human body was loaded with years of parasites and various debris in the manner of an old boat hull.

Previous studies have thus shown a correlation between the genera Escherichia, Blautia, Bifidobacterium, Streptococcus, Lactobacillus and Dorea and the appearance of Alzheimer's disease. On the other hand, the genus Bacteroides could be one of the protective factors of the microbiota. Indeed in the same studies, patients with Alzheimer's disease and mild cognitive impairment show a decrease in the number of Bacteroides, which could be explained by its ability to protect the intestinal barrier.

In September, a group of Chinese scientists, some of whom were employed by the Green Valley Society, published a study in Cell Research that highlighted the link in the mouse between an impaired intestinal microbiome and neuroinflammation.

They reported that oligomannate suppresses bacterial imbalance in the digestive system of mice and reverses cognition disorders. They suggest a new strategy for Alzheimer's treatments by remodeling the intestinal microbiota. However caution was needed because thousands of experimental therapies have cured a considerable number of diseases in mice without ever showing any benefit in humans, but the results of the Phase III clinical trial are changing the game.

Status of marketing Authorization

This new treatment for Alzheimer's disease has been conditionally approved by Chinese regulatory authorities, making it China's first self-developed drug for the treatment of the most common form of dementia, which affects about 50 millions of people around the world. enter image description here

It is a medicine against Alzheimer's disease which derived from marine brown algae. The drug, approved under China's Priority Review System, was jointly developed by Ocean University of China, Shanghai Medical Materials Institute (SIMM) and Shanghai Green Valley Pharmaceuticals during 22 years of intensive research efforts.

Shanghai Green Valley Pharmaceuticals said its drug oligomannate improved the cognitive function of patients with mild-to-moderate Alzheimer's disease compared to placebo in a phase 3 clinical trial. On November 2, the National Medical Products Administration of China said that oligomannate, is safe for the treatment of "mild to moderate Alzheimer's disease and could improve the cognitive functions of patients," adding that more long-term research is still needed after the approval of the drug. ** GV-971 ** is a mixture of acid linear oligosaccharides ranging from dimer to decamer (molecular weight up to ~ 1 kDa).

How it works

Instead of being designed to eliminate accumulations of protein in the brain, as is the case with dozens of experimental treatments for Alzheimer's disease, oligomannate modulates the relationship between the brain and the bacterial communities of the intestine, which is called microbiome.

For the Chinese researchers, dysbiosis of the gut microbiota involves the infiltration of various peripheral immune cells, including CD4 + and CD8 + T cells, B cells, NK (Natural Killer) cells, neutrophils, dendritic cells (CD ) and monocytes, to the brain. Among them, Th1 cells were particularly noted for their close association with the activation of M1 microglia during the progression of Alzheimer's disease. The authors propose that intestinal dysbiosis promotes infiltration of Th1 cells in order to activate with M1 microglia and trigger its differentiation to a pro-inflammatory state.

Clinical trials

Geng Meiyu, a team scientist and professor at SIMM, told at press conference on Sunday, November 3 that oligomannate was effective in rehabilitating the gut microbiota, describing it as "a great innovation." Lü Songtao, chairman of Green Valley Pharmaceuticals, said the drug will be launched in China by the end of the year and a third phase of clinical trials will be conducted in the United States. Green Valley also announced that it will launch a global Phase 3 trial next year in several other countries. The price of this medicine is still being determined.

The next trial would include more people than the approximately 800 people enrolled in the previous phase 3 trial. The completed trial was not designed to demonstrate that the drug had apparently functioned according to the mechanism theorized by the researchers, but the next global trial will attempt to show it.

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This book retraces the main achievements of ALS research over the last 30 years, presents the drugs under clinical trial, as well as ongoing research on future treatments likely to be able stop the disease in a few years and to provide a complete cure in a decade or two.

ALS and cancer

There is a persistent mystery about the causative mechanisms of ALS. The intense work over the last two decades on SOD1 has not helped to conclusively understand its link with the disease. Many SOD1 mutations produce very similar ALS phenotypes. But these mutations have not prevented neurons from functioning properly for several decades, so it is difficult to invoke them to explain the onset of the disease. Even though there is less scientific work on FUS or TDP-43, as their discovery is more recent, the mystery is also complete on how a non-mutated and mis-located TDP-43 protein in the cytoplasm could kill a neuron. The only obvious case is that of C9orf72, where the dipeptide repeats, clearly could not produce functional protein. However, even in this case, it is unclear why ALS only occurs at an advanced age.

PARP is involved in DNA repair

There is a troubling link between cancer and ALS, for example, there is an inverse relationship between the onset of cancer and the onset of ALS. ALS medications also have anti-cancer properties. So, perhaps it's not surprising that they can share a fundamental cause: defects in DNA repair mechanisms. Poly-ADP-ribose polymerases (PARPs) are involved in DNA repair, as are FUS or TDP-43.

During DNA damage or cellular stress, ** PARP ** is activated, resulting in an increase in the amount of poly-ADP-ribose and a decrease in the amount of NAD +.

enter image description here

The poor localization of FUS and TDP-43 in the cytoplasm inhibits the mechanism of DNA repair

FUS and TDP-43 both play a role in the treatment of RNA, including splicing, transcription and transport. The involvement of FUS and TDP-43 in the response to cell genome damage has recently been discovered. In healthy neurons, FUS protects the genome by facilitating dependent recruitment of ** PARP-1 **. The authors report that TDP-43 is an essential component of the end-junction-mediated double-stranded DNA (DNA) repair pathway (NHEJ). TDP-43 is rapidly recruited to double-stranded DNA sites to stably interact with DDR and NHEJ factors, acting in particular as a scaffold for recruitment of the isolating XRCC4-DNA ligase 4 complex at DSB sites. Indeed, the presence of fragmentation of TDP-43 and its aggregation in ALS samples is strongly correlated with the presence of ** PARP-1 ** and cleaved caspase-3.

During apoptosis, PARP moves to the cytoplasm

Caspases are a family of cysteine ​​proteases that play an essential role in programmed cell death. This protease cleaves ** PARP-1 ** into two fragments, leaving it completely inactive to limit the production of poly-ADP-ribose. One of its fragments migrates from the nucleus to the cytoplasm and is considered a target of autoimmunity. At the beginning of 2019, dysregulation of PARylation was found to contribute to the pathogenesis of ALS by promoting protein aggregation.

Although PARylation occurs primarily on PARP proteins, the association of PAR with ALS-related granules has been observed.

Causal chain of ALS

The results of the scientists thus link the pathology of TDP-43 to altered repair of DSB and persistent DDR signaling in motor neuron diseases, and suggest that targeted therapies on double-stranded DNA repair could improve genome instability induced by the toxicity of TDP-43 in motor neuron diseases.

In summary the mechanism causing TDP-43 ALS would be:

  • Mutations of FUS or TDP-43 would render DNA repair ineffective.
  • The intervention of PARP would repair this DNA and relocate TDP-43 in granules in the cytoplasm.
  • This would further aggravate the problems of DNA repair.

A possible therapeutic mechanism

These new findings provide insight into how a DNA repair defect may be associated with FUS and / or TDP-43 neurodegeneration, and raises the question of whether the resolution of DNA ligation problems would be a pathway. promising for the development of neuroprotective treatments.

So mechanisms that would alleviate the burden of PARP (which is different from inhibiting it), would improve the pathology.

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This book retraces the main achievements of ALS research over the last 30 years, presents the drugs under clinical trial, as well as ongoing research on future treatments likely to be able stop the disease in a few years and to provide a complete cure in a decade or two.

What is interleukin 6?

Interleukin 6 (IL6) is a potent pleiotropic cytokine that regulates cell growth and differentiation and plays an important role in the immune response. Deregulated IL6 production is implicated in the pathogenesis of many diseases, such as multiple myeloma, autoimmune diseases and prostate cancer. In addition to other functions, interleukin 6 (IL-6) is involved in the development of immunological and inflammatory reactions. Autoimmune diseases such as rheumatoid arthritis are associated with abnormally high levels of IL-6.

enter image description here

How does it work?

IL-6 had previously been classified as a proinflammatory cytokine, but the anti-inflammatory (beneficial) effects of myokines in general of interleukin-6 of muscle origin are now recognized. So we have a cytokine that can have two modes, one beneficial, the other deleterious, how is that possible?

The explanation could be that the signaling pathways upstream and downstream of IL-6 differ markedly between myocytes and macrophages. It appears that unlike IL-6 signaling in macrophages, which depends on activation of the NFκB signaling pathway, intramuscular IL-6 expression is regulated by a signaling cascade network, including Ca2 + / NFAT and glycogen / p38 MAPK pathways.

IL6 has 2 signaling paradigms: IL6 signaling and IL6 signaling. Although conventional IL6 signaling occurs via IL6 receptors bound to the membrane, IL6 retransformation is induced by a systemic and localized increase in the extracellular soluble IL6 receptor (sIL6R). generated by proteolytic cleavage, called "shedding," of the receptor from the cell surface. These soluble receptors can be activated by IL6 and activate signaling cascades. Thus, IL6 trans-signaling activates the IL6 signaling pathways in cells that do not express the IL6 receptor.

Are there different reactions to IL6 in humans?

In humans, there are at least two alleles for the IL6 receptor (Asp358Ala, A / C, rs2228145), the A allele (Asp358) being the main allele and the C allele (Ala358), the variant allele. The expression of the IL6 receptor (IL6R) is favored by the C allele. In individuals with IL6R allele, increased receptor expression improves both localized and systemic IL6 transsignalization in the presence of IL6. This allele is associated with certain diseases such as asthma.

Why would IL6 have an interest in treating ALS?

Perhaps because a patient with ALS was reported to have had a remission in 2014 by consuming lunasin, a soy peptide, researchers have wondered whether IL6 transsignalization could play a role. potential in ALS.

How did the scientists proceed?

IL6 and sIL6R levels were measured in samples in a cohort of patients with ALS and compared to healthy patients. Their results suggest that the IL6R C allele influences IL6 signaling in the central nervous system of patients with ALS. In a second cohort of ALS subjects with more definite clinical data, the presence of the IL6R C allele was associated with a more rapid progression of the disease. These results suggest that identifying patients with the IL6R C allele may provide useful information for predicting disease progression and identifying those who may benefit most from IL6R blocking therapies.

What happened in 2014

ALS experts will recall that in 2014 Mike McDuff, who has ALS, experienced dramatic improvements in speech, swallowing and strength in ALS. lunasin.

Dr. Bedlack from SLA Duke Clinic confirmed that Mike McDuff's symptoms had actually improved dramatically. A clinical trial was then conducted to evaluate the interest of lunasin in the case of ALS. Fifty people with ALS were put on the diet containing exactly the lunasin Mike McDuff had followed and were followed for one year. The clinical trial was completed in September 2017. Unfortunately, there is no evidence that lunasin slowed, stopped, or reversed ALS in clinical trial participants. Gastrointestinal adverse events were more frequent than expected in the trial participants, including cases of constipation severe enough to warrant hospitalization.

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This book retraces the main achievements of ALS research over the last 30 years, presents the drugs under clinical trial, as well as ongoing research on future treatments likely to be able stop the disease in a few years and to provide a complete cure in a decade or two.

Specific regions of the brain are atrophied in neurodegenerative diseases, however, physiological differences from one patient to another make it difficult to predict the progression of neurodegeneration in a specific individual.

An important theory of the progression of neurodegenerative diseases is that misfolded pathological proteins move from one neuron to another via trans-synaptic propagation. Seeley and his colleagues, but also others like H Braak have previously proposed, based on this idea, that the disease begins in an area of ​​the brain, the epicenter, and spreads into new, functionally connected regions.

Most of the information in this regard came from cross-sectional data. It remained to be seen whether such a model predicted longitudinal atrophy in individual patients. In the present study, the authors sought to do just that in patients with frontal variant behavioral dementia (bvFTD) or the semantic variant of primary progressive aphasia (SVPPA), two forms of frontotemporal dementia with schemas distinct from atrophy. They hypothesized that, in a particular disorder, individual patients would have distinct epicenters that would dictate differences in the overall progression of the disease.

In general, epicondensons overlap in patients with the same syndrome. In patients with bvFTD, they most often resided in the anterior cingulate cortex and fronto-sinus cortex. In people with svPPA, the epicenter tended to be close to the anterior temporal lobe. Even in this case, the exact location of the epicenters still varied considerably from person to person. Interestingly, although these epicenters have always shown signs of atrophy, they were not necessarily the areas of greatest loss of volume. Within each disease, patterns of atrophy differed considerably from person to person.

Scientists led by Jesse Brown and Bill Seeley of the University of California, San Francisco, used a single structural MRI in 72 patients with frontotemporal dementia to predict which regions of their brain would succumb to the disease.

They were able to determine the probable origin of the disease - its epicenter - and used functional connectivity maps to extrapolate areas that may subsequently atrophy during disease progression. Their predictions seem indeed correlated with the loss of brain volume in the following years. the authors suggest that this method provides an individualized biomarker for clinical trials and also for early diagnosis. Brown and colleagues show that the key biology at play in neurodegenerative diseases involves the functional physiology of large-scale brain networks that support mental functioning. As in previous studies, the methods used in this study do not differentiate competing patterns of networked neurodegeneration.

To identify areas that could atrophy as the disease progressed, researchers developed a forecasting model that took into account three factors: the functional link of a region to the epicenter, the narrowing of its closest neighbors and the loss of reference volume. From there, the researchers determined the probable atrophy patterns of 42 volunteer patients of bvFTD and 30 patients with svPPA. These participants then performed an average of three additional separate analyzes of six to 14 months, and the researchers compared the expected results to the actual loss.

Two aspects of the study are particularly noteworthy. The first is the idea of ​​a model of personalized prediction of longitudinal atrophy of the brain, based on the hypothesis of trans-neuronal propagation. The second is the introduction of a concept called "nodal risk", which is a measure of the regional risk of future atrophy based on the degree of basic atrophy in highly functionally connected regions. Compared to previous group-level approaches, an individualized metric of the rate and directionality of impending brain atrophy has important potential ramifications for clinical practice and clinical trials. For example, because cerebral atrophy is closely related to the clinical progression of the disease, this method based on connectivity can be useful for the prognosis of various neurodegenerative diseases. In addition, the placebo and treatment groups could be carefully compared to the atrophy rates expected during clinical trials.

In addition, identifying a group of "fast progressors" may allow for more effective screening of drug candidates (ie, shorter duration and fewer people).

The researchers found that the rate of volume loss differed across brain regions. For the most part, these patterns of atrophy were quite similar, with a correlation coefficient of 0.65. For 16 patients, including 13 with bvFTD, the model did not predict volume loss, with an average correlation coefficient of -0.04. Most of these patients had limited initial atrophy and a confused epicenter. The strongest contraction occurred not in the epicentres themselves, but in their first-degree neighbors. Perhaps the epicenter had already degenerated as much as it would, while the first-degree neighbors were just beginning, the authors said. "This has fundamental implications for clinical trials that would use indexes derived from imaging as a result," wrote Bejanin. "The best areas for evaluating the effect of disease-modifying drugs should not be those that are primarily affected by the disease, nor the most atrophied, but those most connected to these areas."

The method requires important information about the emerging neurodegenerative pattern, which may hinder application in the early stages of the disease. It is not yet refined enough to be used in clinical trials. In this study, grouped data on the functional connectome of a group of healthy people were used to predict connectivity, but using a patient's own connectome would likely improve predictions. With greater accuracy, this model could provide a proof-of-principle indicator for early-to-intermediate-stage clinical trials. For example, if a therapy causes less atrophy than expected, it could encourage stakeholders to conduct a confirmatory test.

However, although it is highly correlated, atrophy is not equivalent to the underlying pathology. Thus, some of the direct effects of the pathology on cognition and / or behavior (i.e., mediated by atrophy) may not be captured.

a more distant goal is to predict enough atrophy to predict the symptoms that patients may expect in the future. This model may be useful in other neurodegenerative diseases, including Alzheimer's disease, although the dual proteininopathy of Aβ and Tau protein is likely to make the situation more complicated.

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This book retraces the main achievements of ALS research over the last 30 years, presents the drugs under clinical trial, as well as ongoing research on future treatments likely to be able stop the disease in a few years and to provide a complete cure in a decade or two.

Living organisms use energy in a radically different way than immune cells in vitro.

For years, scientists have used cells grown in Petri dishes to study the metabolic processes that fuel the immune system. But a new article suggests that living organisms use energy in a radically different way from immune cells in vitro.

The scientific consensus since Warburg's work is that immune cells, called T cells, convert glucose into energy to fuel cellular function. In fact there are different mechanisms by which a cell can get energy, the so-called metabolism or also respiration.

How do the cells get energy?

On the one hand, we distinguish anabolism, which represents all the biosynthetic pathways of cellular constituents, and on the other hand, catabolism, which represents all the pathways of degradation of these cellular constituents into small molecules to release them. energy by oxidation or to rebuild other cellular constituents.

Catabolism can be differentiated between aerobic and anaerobic respiration. Aerobic respiration includes glycolysis, oxidative decarboxylation of pyruvate, citric acid cycle, oxidative phosphorylation.

The main degradation pathway is glycolysis, where sugars such as glucose and fructose are converted to pyruvate and generate ATP. Pyruvate is an intermediate in several metabolic pathways, but the majority is converted to acetyl-CoA by aerobic glycolysis (with oxygen) and introduced into the citric acid cycle.

Lipids are catabolized by hydrolysis to free fatty acids and glycerol. Glycerol enters glycolysis and the fatty acids are decomposed by beta-oxidation to release acetyl-CoA, which is then introduced into the citric acid cycle.

There are two important microbial methane formation pathways, by carbonate reduction (respiration) and acetate fermentation.

Warburg hypothesized that cancer growth is caused by energy-generating tumor cells (such as, for example, adenosine triphosphate / ATP) primarily through anaerobic degradation of glucose (called fermentation or anaerobic respiration). This contrasts with healthy cells, which primarily generate energy from the oxidative decomposition of pyruvate. Pyruvate is a final product of glycolysis and is oxidized in mitochondria. Therefore, according to Warburg, cancer should be interpreted as mitochondrial dysfunction.

For multicellular organisms, during brief periods of intense activity, muscle cells use fermentation to supplement ATP production from slower aerobic respiration.

What was discovered?

Jones and colleagues found that T cells in a living system use glucose as a building block for DNA replication and other maintenance tasks, in addition to converting glucose into raw energy. They also discovered that the way T cells treat glucose evolves during an immune response. The metabolism of glucose in T cells changes dynamically during an immune response. Glucose-dependent serine biosynthesis promotes T-cell proliferation in vivo.

enter image description here

This suggests that T cells can use resources differently in the body when they are fighting a bacterial infection such as Listeria or a disease like cancer.

Naïve CD8+ T cells differentiating into effector T cells increase glucose uptake and transition from resting metabolism to anabolic metabolism. Although much is known about the metabolism of cultured T cells, the way in which T cells utilize nutrients during the in vivo immune response is less well defined. The researchers therefore combined the bioenergetic profiling and 13C glucose perfusion techniques to study the metabolism of CD8+ T cells responding to Listeria infection.

In contrast to the in vitro activated T cells, which exhibit Warburg metabolism, physiologically activated CD8+ T cells exhibited higher levels of oxidative metabolism, higher bioenergetic capacity, differential pyruvate utilization, and high 13C carbon flux. glucose to the anabolic pathways, including the biosynthesis of nucleotides and serine. The glucose-dependent serine biosynthesis induced by the Phgdh enzyme was essential for the expansion of CD8+ T cells in vivo.

Our immune cells do not work in isolation

"It's like watching animal behavior in a zoo or in the wild - our immune cells do not work in isolation - they work with a host of other cells and factors that influence how and when they are used. of energy, "said Russell Jones, Ph.D., lead author of the study and head of the Metabolic and Nutritional Programming Group at the Van Andel Institute. "Understanding cell metabolism is a crucial part of therapeutic development, and our results reinforce the need to study these cells in an environment as close as possible to nature."

The findings have profound implications for how scientists study the complex and interconnected systems that underlie health and disease and how they translate this information into new diagnostic and treatment strategies.

"Immune cells react much more dynamically to infections and diseases than we previously thought," Jones said. "For a while, we're at a stage of metabolism research, it's like we're in the dark under a lamppost, we could only see in front of us, and these results will help us better understand this. which immune cells need for optimal function. "

Which suite will be given?

The results were made possible by a new method developed in consultation with collaborator Ralph DeBerardinis, MD, Ph.D., who allowed Jones and his colleagues to map how T cells use nutrients in living organisms. They have developed a 13C infusion method to study T cell metabolism in vivo

"In the future, this new mapping technique will be invaluable in pursuing studies of specific diseases," said Eric Ma, Ph.D., lead author of the study and a postdoctoral researcher in the field. Jones's laboratory.

In the future, the team plans to design human studies to measure how T cells use glucose and other nutrients when they respond to pathogens or other diseases such as injuries or diseases such as cancer.

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This book retraces the main achievements of ALS research over the last 30 years, presents the drugs under clinical trial, as well as ongoing research on future treatments likely to be able stop the disease in a few years and to provide a complete cure in a decade or two.

History of brain organoids

Cerebral organoids have provided a means of generating complex, three-dimensional and in vitro models of human neurons that summarize, in part, neuronal diversity and aspects of the physical architecture of the developing brain, such as stratification.

The researchers led by Lancaster generated the first cortical organoids in 2013. They seeded stem cells in a three-dimensional matrix with a nutrient bath. Within a month, the cells have differentiated and formed small structures of a few millimeters, looking like miniature brains. These cell layers mimicked structures such as the hippocampus and cerebral cortex. Without blood supply, however, the neurons at the center of these organoids decayed and eventually died.

The brain organoids as models

The organoids of the human brain have become a promising model for the study of neural development and neurological disorders, including Alzheimer's disease. This model has enormous potential for testing therapeutic agents and determining their permeability across the blood-brain barrier.

However, it remains difficult to generate an authentic model that summarizes the complex structure and function of the human brain. Brain organoids can not fully capture the cellular diversity of the brain. The absence of microglia and blood vessels is particularly troublesome, if one wants to apply these organoids to the study of Alzheimer's disease. The absence of a vascular system causes the organoids to become limited in size and contain a largely necrotic nucleus due to the inability of the nutrient fluid to enter the center of the structure.

What is the contribution of Cakir and his colleagues?

Cakir and his colleagues established an organo-cerebral model with a vascular-like system that works in implanted mice. This system is unique in many respects compared to previously published brain organoids.

They generated vascularized human cortical organoids by expressing an endothelial transcription factor. They discovered that such human cortical organoids developed a complex vascular network. The vascularized human cortical organoids were in good health compared to nonvascularized equivalent organoids.

enter image description here

When the authors compared cellular transcriptomes, they found that vascularized human cortical organoids expressed more mature neuronal markers, as well as markers of other cell types, particularly those involved in the formation of neurovascular units. including tight junction markers, astrocyte and pericytic proteins, and transporters.

Application to Alzheimer's disease

In addition, the treatment of vascularized human cortical organoids with oligomeric Aβ42 resulted in tight junction malformation and disruption of the blood-brain barrier, indicating that the blood-brain barrier structure responds to exogenous factors. The vascularized human cortical organoids were grafted into mice and formed functional vascular connections with the host mouse.

With respect to Alzheimer's disease, the authors have shown that oligomeric synthetic Aβ preparations selectively perturb the permeability of the blood-brain barrier in their vascularized human cortical organoids. An interesting question is: Is it possible that high levels of oligomeric Aß could compromise cerebrovascular integrity and allow therapeutic biological products and small molecules to pass freely across the blood-brain barrier of patients with Alzheimer's disease?

How to apply brain organoids technology to the study of neurodegenerative diseases?

First, given the known variability among organoids, future studies should address the fundamental issue of reproducibility and functional homogeneity. In addition, the current method for modeling fetal brain-like organoids may be somewhat limited for summarizing a mature brain environment. The vasculature of the adult brain is much more complex, including in the perivascular spaces, which contribute to the elimination of toxic solutes such as Aβ.

The incorporation of iPSC microglia into organoids (Abud et al., 2017), paves the way for the creation of complex, multicellular and human in vitro models to study the mechanisms of non-cellular autonomic diseases in Alzheimer.

It will be very interesting now to investigate whether the blood vessels are able to constrict and dilate, if the pericytes can contract and relax, if the vascularized human cortical organoids would be useful for studying neurovascular coupling, if there is venous and arterial flow and many others questions. The next years of research using vascularized brain organoids will provide more answers and will undoubtedly enable many breakthroughs in the cerebrovascular field.

http://www.ncbi.nlm.nih.gov/pubmed/31591580

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Ce livre retrace les principales réalisations de la recherche sur la SLA au cours des 30 dernières années. Il présente les médicaments en cours d’essai clinique ainsi que les recherches en cours sur les futurs traitements susceptibles d’ici quelques années, d’arrêter la maladie et de fournir un traitement complet en une décennie ou deux.

I did published a book on ALS research:

Caveats: I am not a doctor, nor a scientist and English is not my mother-tongue.

Here are some take home points:

  • Scientists are obsessed by SOD1 (2% of all ALS cases) as a model for ALS. However there is overwhelming evidence this is a fruitless pursuit.

  • There are nearly no treatments:

    • For all pALS, a very imperfect treatment is Nurown, but it exists!
    • For SOD1 pALS (2% of all cases), there are two treatments that are in clinical trials.
    • For the other (98%) pALS there are no drugs in the pharmaceutical pipeline. However for most pALS (TDP-43 / 95% of all cases) there are genetic therapies that have recently been published by scientists, but if no one tries to defend them, it will take another 10 years before they are marketed.
  • The ALS research is bizarre, scientists often contradict colleagues but nobody seems to care. The consensus still cites theories that have been disproved since decades, like glutamate excitotoxicity. ALS is certainly not one homogeneous disease, but it is still treated as such by scientists. Animal models of ALS have little value in translation of drugs to humans, but moreover often ALS research is done on insects (that have an exoskeleton), or even on unicellular organisms. There is no formalism anywhere, little effort to falsify any thesis.

What can you expect to find in this book:

  • A brief description of ALS and its common variants (PLS, PMA, etc): ~7 pages

  • A description of the cell in general, from an ALS point of view : ~15 pages

  • A strong focus on the neuronal cells, again with ALS in mind: ~34 pages

  • The main themes in ALS research (dying forward, excitotoxicity, virus, etc): ~40 pages

  • Main achievements of ALS research (SOD1, TDP-43, discovery, etc): ~113 pages

  • A focus on clinical trials and 28 drugs: ~37 pages

  • Different kind of therapies (MSC, ASO, etc): ~20 pages

  • A possible new therapy for ALS (if only a company had the will to investigate it!): ~20 pages

  • Futures therapies that are researched now (creating or grafting new neurons): ~17 pages

This is not an easy read, so I tried to explain terms, provide a large section on the neuronal cell at the beginning, and wrote 276 footnotes.

There are no speculations, nor pseudo scientific babble. I am not overly kind either with ALS scientists, clearly they can do much better.

Jean-Pierre Le Rouzic

My book on ALS research

Alzheimer's, FTD, bvAD and bvFTD

The signs of Alzheimer's disease, which is characterized by a selective amnesia, for example of his relatives, are well known. Fronto-Temporale Dementia (FTD), it is associated with significant changes in social and personal behavior, apathy, blunted emotions and language deficits. The FTD shares gene mutations with ALS. The behavioral variant of frontotemporal dementia (bvFTD) is characterized by changes in social behavior and behavior, with loss of social awareness and insufficient control of impulses.

How to differentiate bvAD from bvFTD?

Singleton and colleagues have shown that Alzheimer's disease, which typically leads to amnesic dementia, may also have behavioral variants (bvAD) and that the phenotype determinant is the anatomy of neurodegeneration.

enter image description here

In a small percentage of people with Alzheimer's disease, early behavioral changes, such as disregard for social norms or loss of empathy, may lead physicians to misdiagnose a behavioral variant of front-line dementia. temporal. How can they better distinguish this variant of Alzheimer's disease? The diagnosis between bvAD and bvFTD is clinically very difficult without imaging.

While structural MRI does not make a significant distinction between bvAD and typical Alzheimer's disease, metabolic PET shows a decrease in the activity of frontense and anterior default mode networks in bvAD, similar to bvFTD .

What is a default neurology network?

In neuroscience, the default network (DMN) is composed of interacting brain regions, whose activity is highly correlated with each other and distinct from other brain networks.

Initially, it was assumed that the default mode network was most often active when a person did not focus on the outside world and his brain was dormant, such as daydreaming or mental observation. However, it is now known that this can contribute to experience elements related to the performance of external tasks. He is also active when the individual thinks of others, thinks of himself, remembers the past and prepares himself for the future. Although the DMN was initially noted as disabled in some goal-oriented tasks and is sometimes referred to as a negative-task network, it may be active in other objective-oriented tasks, such as social work memory or autobiographical tasks. DMN is not correlated with other brain networks such as attention networks.

Studies on DMN have shown disturbances in the DMN of people with Alzheimer's disease and Autism Spectrum Disorder.

The value of neuroimaging for the diagnosis of bvAD

"This is the first study focused on bvAD to show such a variety of neuroimaging features," Singleton said. "This suggests that FDG-PET is more accurate in differentiating these diseases than MRI."

In a previous structural MRI study in 2015, Ossenkoppele and colleagues expected to find frontal cortical atrophy in people with bvAD, but were puzzled to find none.

Singleton and his colleagues examined the 150-person MRI and FDG-PET scans recruited at the University of California, San Francisco, and the University of Berkeley. BvAD was diagnosed in 29 patients, 28 in patients with typical Alzheimer's disease, 28 in patients with DVBt and 65 in cognitively normal subjects.

How does a TEP-FDG work?

Positron emission tomography (PET) scanners detect photons of light energy and construct three-dimensional images from the photons they receive. Scientists can use this ability to detect photons for medical diagnostic purposes if they know where these photons come from and what they represent.

The cells of the human body use glucose, a sugar, as the main source of energy to trigger all reactions and growth. FDG is a glucose molecule to which is attached a radioactive fluorine atom. It is radioactive, but it is not powerful enough to pose a significant risk to health.

When the FDG decomposes, it emits a particle called positron, which then divides into two photons. These are the photons produced by the FDG that the PET scanner detects. As FDG collects in highly active cells such as tumors, most photons come from these regions.

enter image description here Author Jens Maus http://jens-maus.de/

Metabolism and Alzheimer's

On PET-FDG scans, Singleton and colleagues found a pattern in patients with bvAD that was largely consistent with patients with typical Alzheimer's disease: hypometabolism in the posterior cingulate cortex, precuneus, and temporoparietal lateral. In addition, patients with bvAD had subtle metabolic deficits in fronto-insular areas, including the right lateral frontal lobe and bilateral insula, which did not appear in typical Alzheimer's disease (see image below). -above). This earlier pattern was more similar to that observed in sweeping examinations of patients with bvFTD.

The researchers also measured the uptake of FDG through the brain networks to look for changes in metabolic connectivity. Deficiency in the posterior default network (DMN) was lower in patients with bvAD and typical Alzheimer's disease than in controls, suggesting that these areas were affected in both types of AD. However, less absorption at the previous DMN distinguished bvAD from typical Alzheimer's disease and corresponded to the trend seen in bvFTD.

The researchers found no difference in terms of subcortical atrophy or white matter lesion between typical and bvAD.

These data suggest that common metabolic and connectivity deficits are at the basis of the behavioral phenotype shared by patients with bvAD and bvFTD.

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This book traces the main achievements of ALS research over the last 30 years. He presents the drugs under clinical trial as well as ongoing research on future treatments likely within a few years, to stop the disease and provide complete treatment in a decade or two.

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