Myostatin

[Michael Scally MD]

[OA] Downregulation of Myostatin Pathway in Neuromuscular Diseases May Explain Challenges of Anti-Myostatin Therapeutic Approaches

Muscular dystrophies are characterized by weakness and wasting of skeletal muscle tissues. Several drugs targeting the myostatin pathway have been used in clinical trials to increase muscle mass and function but most showed limited efficacy.

Here we show that the expression of components of the myostatin signaling pathway is downregulated in muscle wasting or atrophying diseases, with a decrease of myostatin and activin receptor, and an increase of the myostatin antagonist, follistatin.

We also provide in vivo evidence in the congenital myotubular myopathy mouse model (knock-out for the myotubularin coding gene Mtm1) that a down-regulated myostatin pathway can be reactivated by correcting the underlying gene defect.

Our data may explain the poor clinical efficacy of anti-myostatin approaches in several of the clinical studies and the apparent contradictory results in mice regarding the efficacy of anti-myostatin approaches and may inform patient selection and stratification for future trials.

Mariot V, Joubert R, Hourde C, et al. Downregulation of myostatin pathway in neuromuscular diseases may explain challenges of anti-myostatin therapeutic approaches. Nat Commun 2017;8:1859. https://www.nature.com/articles/s41467-017-01486-4

 

[Cramps88]

By far one of the most interesting threads on the forum.

 

[heady muscle]

@Michael Scally MD

I may have missed it in this thread; Would myostatin inhibitors affect the organs i.e enlarge the heart?
Thanks

 

[Michael Scally MD]

@Michael Scally MD

I may have missed it in this thread; Would myostatin inhibitors affect the organs i.e enlarge the heart?
Thanks

There is a report to this effect. A question could be differential effects of ill vs healthy. IOW, an adverse effect in the healthy [BB].

 

[heady muscle]

There is a report to this effect. A question could be differential effects of ill vs healthy. IOW, an adverse effect in the healthy [BB].

Makes sense. Thank you sir.

 

[master.on]

Genetic Engineering Home Lab Kit

Human Myostatin Knock-Out Targeting CRISPR-Cas9 Plasmid

Lab kit?
Has it being tried already?
Did anyone die from it?

Any less risky protocol?
Something like
1 you draw your own blood,
2 use the lab kit on drawn blood
3 filter blood to exclude blood cells (optional)
25 microns – White blood cells
8 microns – Red blood cells
2 microns – Bacteria
Baldwin Filters | Tech Tips
4 reinject plasma full of growth factors

 

[heady muscle]

Genetic Engineering Home Lab Kit

Human Myostatin Knock-Out Targeting CRISPR-Cas9 Plasmid

DIY Human CRISPR Guide

"This product is not injectable or meant for direct human use. The DNA needs to replicated and purified before use in human cells."

 

[master.on]

DIY Human CRISPR Guide

"This product is not injectable or meant for direct human use. The DNA needs to replicated and purified before use in human cells."

The good thing is that the kit only costs $20
the bad thing is that you first need to win a Nobel prize to know how to use it

Can you suggest the-odin to start making kits to grow your own genetically modified recombinant bacteria that makes GH or IGF-1?

 

[Michael Scally MD]

[OA] In Vivo Target Gene Activation via CRISPR/Cas9-Mediated Trans-Epigenetic Modulation [Follistatin]

Phenotypic Enhancement of Muscle Mass Induced by In Vivo CRISPR/Cas9 TGA

The next critical test of the CRISPR/Cas9 TGA system was to activate an endogenous gene (rather than an exogenous reporter) and to determine whether induced levels of expression were sufficient to cause a phenotype. We targeted the mouse follistatin (Fst) gene because Fst overexpression increases muscle mass. It was successful.

Highlights
· A CRISPR/Cas9 system transcriptionally activates endogenous target genes in vivo
· Recruiting the transcriptional machinery induces trans-epigenetic remodeling
· Inducing target gene expression leads to physiological phenotypes in postnatal mammals
· The system ameliorates symptoms associated with several mouse models of human diseases

Current genome-editing systems generally rely on inducing DNA double-strand breaks (DSBs). This may limit their utility in clinical therapies, as unwanted mutations caused by DSBs can have deleterious effects. CRISPR/Cas9 system has recently been repurposed to enable target gene activation, allowing regulation of endogenous gene expression without creating DSBs. However, in vivo implementation of this gain-of-function system has proven difficult.

Here, we report a robust system for in vivo activation of endogenous target genes through trans-epigenetic remodeling. The system relies on recruitment of Cas9 and transcriptional activation complexes to target loci by modified single guide RNAs.

As proof-of-concept, we used this technology to treat mouse models of diabetes, muscular dystrophy, and acute kidney disease. Results demonstrate that CRISPR/Cas9-mediated target gene activation can be achieved in vivo, leading to measurable phenotypes and amelioration of disease symptoms. This establishes new avenues for developing targeted epigenetic therapies against human diseases.

Liao H-K, Hatanaka F, Araoka T, et al. In Vivo Target Gene Activation via CRISPR/Cas9-Mediated Trans-epigenetic Modulation. Cell. Redirecting

 

[heady muscle]

The good thing is that the kit only costs $20
the bad thing is that you first need to win a Nobel prize to know how to use it

Can you suggest the-odin to start making kits to grow your own genetically modified recombinant bacteria that makes GH or IGF-1?

Nope, my degree is in psychology. I had to take pharma classes, but this shit is beyond me. I was responding to crispy. You do it first! lol

 

[master.on]

Nope, my degree is in psychology. I had to take pharma classes, but this shit is beyond me. I was responding to crispy. You do it first! lol

Do you get lots of crazy girls?
They seem to like psychologists.

 

[mands]

[OA] In Vivo Target Gene Activation via CRISPR/Cas9-Mediated Trans-Epigenetic Modulation [Follistatin]

Phenotypic Enhancement of Muscle Mass Induced by In Vivo CRISPR/Cas9 TGA

The next critical test of the CRISPR/Cas9 TGA system was to activate an endogenous gene (rather than an exogenous reporter) and to determine whether induced levels of expression were sufficient to cause a phenotype. We targeted the mouse follistatin (Fst) gene because Fst overexpression increases muscle mass. It was successful.

Highlights
· A CRISPR/Cas9 system transcriptionally activates endogenous target genes in vivo
· Recruiting the transcriptional machinery induces trans-epigenetic remodeling
· Inducing target gene expression leads to physiological phenotypes in postnatal mammals
· The system ameliorates symptoms associated with several mouse models of human diseases

Current genome-editing systems generally rely on inducing DNA double-strand breaks (DSBs). This may limit their utility in clinical therapies, as unwanted mutations caused by DSBs can have deleterious effects. CRISPR/Cas9 system has recently been repurposed to enable target gene activation, allowing regulation of endogenous gene expression without creating DSBs. However, in vivo implementation of this gain-of-function system has proven difficult.

Here, we report a robust system for in vivo activation of endogenous target genes through trans-epigenetic remodeling. The system relies on recruitment of Cas9 and transcriptional activation complexes to target loci by modified single guide RNAs.

As proof-of-concept, we used this technology to treat mouse models of diabetes, muscular dystrophy, and acute kidney disease. Results demonstrate that CRISPR/Cas9-mediated target gene activation can be achieved in vivo, leading to measurable phenotypes and amelioration of disease symptoms. This establishes new avenues for developing targeted epigenetic therapies against human diseases.

Liao H-K, Hatanaka F, Araoka T, et al. In Vivo Target Gene Activation via CRISPR/Cas9-Mediated Trans-epigenetic Modulation. Cell. Redirecting

I'm wondering and haven't looked to far into this...

When a gene is activated or deactivated can it be deactivated or re-activated.

For example if the "gene" that produces myostatin is deactivated can it be re-activated after the user's desired effects take place?

mands

 

[heady muscle]

Do you get lots of crazy girls?
They seem to like psychologists.

No, only, lonely fat ugly ones with giant wet pussies! I haven't been in the field for about 20 odd years. Went into electrical engineering instead. More crazy people, but I don't have to listen to their shit if I don't want to.

 

[Michael Scally MD]

Myostatin Inhibitors: Revolutionary or Dangerous?
Myostatin Inhibitors: Revolutionary or Dangerous? – Henry Flores

 

[master.on]

Myostatin Inhibitors: Revolutionary or Dangerous?
Myostatin Inhibitors: Revolutionary or Dangerous? – Henry Flores

Is Follistatin expected to be fairly safe?
The article doesn't mention it.

What happened to the german kid born without myostatin?
Did he grow/age OK?

 

[heady muscle]

Myostatin Inhibitors: Revolutionary or Dangerous?
Myostatin Inhibitors: Revolutionary or Dangerous? – Henry Flores

Interesting.

I picked up some yk 11. I am going to have it tested first before I use it. Not sure what to expect (besides the bullshit I have read all over the place).

 

[Michael Scally MD]

Scholar Rock scoops $47M to trial SMA drug SRK-015, an inhibitor of the supracellular activation of latent myostatin, to improve outcomes in this population by boosting muscle strength and motor function. http://www.scholarrock.com/news/press-releases/scholar-rock-announces-47-million-series-c-financing-advance-innovative-pipeline-sma-immuno-oncology-fibrosis-iron-restricted-anemias/

Scholar Rock has raised $47 million to take its treatment for spinal muscular atrophy (SMA) into the clinic. SRK-015 for Spinal Muscular Atrophy (SMA) - Scholar Rock

Companies including Novartis, Amgen spinout Atara and Shire have swung and missed at myostatin in recent years. Scholar Rock, which ceded a significant head start to these and other companies, has always maintained SRK-015’s targeting of upstream processes gives it an edge over the competition. And it and its investors’ belief in that idea has survived the clinical failures of other myostatin drugs.

 

[Michael Scally MD]

Scholar Rock scoops $47M to trial SMA drug SRK-015, an inhibitor of the supracellular activation of latent myostatin, to improve outcomes in this population by boosting muscle strength and motor function. http://www.scholarrock.com/news/press-releases/scholar-rock-announces-47-million-series-c-financing-advance-innovative-pipeline-sma-immuno-oncology-fibrosis-iron-restricted-anemias/

Scholar Rock has raised $47 million to take its treatment for spinal muscular atrophy (SMA) into the clinic. SRK-015 for Spinal Muscular Atrophy (SMA) - Scholar Rock

Companies including Novartis, Amgen spinout Atara and Shire have swung and missed at myostatin in recent years. Scholar Rock, which ceded a significant head start to these and other companies, has always maintained SRK-015’s targeting of upstream processes gives it an edge over the competition. And it and its investors’ belief in that idea has survived the clinical failures of other myostatin drugs.

Le VQ, Iacob RE, Tian Y, et al. Tolloid cleavage activates latent GDF8 by priming the pro-complex for dissociation. bioRxiv 2017. Tolloid cleavage activates latent GDF8 by priming the pro-complex for dissociation

Growth differentiation factor 8 (GDF8)/Myostatin is a latent TGF-β family member that potently inhibits skeletal muscle growth. Here, we compared the conformation and dynamics of precursor, latent, and Tolloid-cleaved GDF8 pro-complexes to understand structural mechanisms underlying latency and activation of GDF8. Negative stain electron microscopy (EM) of precursor and latent pro-complexes reveals a V-shaped conformation that is unaltered by furin cleavage and sharply contrasts with the ring-like, cross-armed conformation of latent TGF-β1. Surprisingly, Tolloid-cleaved GDF8 does not immediately dissociate, but in EM exhibits structural heterogeneity consistent with partial dissociation. Hydrogen-deuterium exchange was not affected by furin cleavage. In contrast, Tolloid cleavage, in the absence of prodomain-growth factor dissociation, increased exchange in regions that correspond in pro-TGF-β1 to the α1-helix, latency lasso, and β1 strand in the prodomain and to the β6′-7′ strands in the growth factor. Thus, these regions are important in maintaining GDF8 latency. Our results show that Tolloid cleavage activates latent GDF8 by destabilizing specific prodomain-growth factor interfaces and primes the growth factor for release from the prodomain.

 

[heady muscle]

Do you get lots of crazy girls?
They seem to like psychologists.

Yes,
I married one. Now I need help!

 

[Michael Scally MD]

[OA] Supraphysiologic Administration of GDF11 Induces Cachexia in Part by Upregulating GDF15

Highlights
· Increased levels of GDF11 cause increased circulating Activin A and GDF15 in mice
· Supraphysiologic levels of GDF11 induce cachexia, anorexia, and muscle loss
· Blockade of GDF15 spares anorexia, but not muscle loss
· Blockade of the GDF11 receptor ActRII spares muscle loss and decreases anorexia

The age-related effects of GDF11 have been a subject of controversy. Here, we find that elevated GDF11 causes signs of cachexia in mice: reduced food intake, body weight, and muscle mass. GDF11 also elicited a significant elevation in plasma Activin A, previously shown to contribute to the loss of skeletal muscle. The effects of GDF11 on skeletal muscle could be reversed by administration of antibodies to the Activin type II receptors.

In addition to the effects on muscle, GDF11 increased plasma GDF15, an anorectic agent. The anorexia, but not the muscle loss, could be reversed with a GDF15-neutralizing antibody. GDF15 upregulation is due to GDF11-induced recruitment of SMAD2/3 to the GDF15 promoter. Inhibition of GDF15 can restore appetite but cannot restore the GDF11-induced loss of muscle mass, which requires blockade of ActRII signaling.

These findings are relevant for treatment of cachexia.

Jones JE, Cadena SM, Gong C, et al. Supraphysiologic Administration of GDF11 Induces Cachexia in Part by Upregulating GDF15. Cell Reports 2018;22:1522-30. Redirecting