Lets Talk About Peptides...

[BiggerStronger]

I'm finding these new peptides very interesting so I would like to compile some information that will hopefully get the ball rolling in terms of research and laboratory work.

Here we go:

Exogenous ghrelin modulates release of pro-inflammatory and anti-inflammatory cytokines in LPS-stimulated macrophages through distinct signaling pathways.
Waseem T, Duxbury M, Ito H, Ashley SW, Robinson MK.

Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass.

BACKGROUND: Ghrelin, an orexigenic 28-amino-acid peptide, has been studied primarily in relation to the control of appetite and fat metabolism. In addition to these well-known functions, ghrelin, and its target receptors, growth hormone secretagogue receptors (GHS-Rs), have been localized to neutrophils, lymphocytes, and macrophages, which suggests that ghrelin may be involved in immune modulation. METHODS: To assess the therapeutic role of ghrelin in production of pro-inflammatory and anti-inflammatory cytokines, the effects of exogenous ghrelin administration on the regulation of cytokine release in lipopolysaccharide (LPS)-activated murine RAW 264.7 macrophages were analyzed. RESULTS: Ghrelin and GHS-Rs are expressed in murine macrophages. In addition, exogenous ghrelin inhibited the production of pro-inflammatory cytokines IL-1beta and TNF-alpha in LPS-stimulated murine macrophages in a dose dependent and time-dependent fashion. Exogenous ghrelin pretreatment resulted in a decrease in LPS-induced NFkappaB activation and was presumably the reason for this ghrelin-mediated effect. In contrast to these findings, exogenous ghrelin significantly augmented the release of the anti-inflammatory cytokine IL-10 in a dose-dependent and time-dependent fashion from LPS-stimulated murine macrophages. Ghrelin administration enhanced activation of p38 MAPK, which is known to control the release of IL-10 in macrophages independent of the NFkappaB pathway. These effects of ghrelin on both pro-inflammatory and anti-inflammatory cytokines were offset when a specific GHS-R receptor antagonist was added to the culture media. CONCLUSIONS: These data suggest that ghrelin has potent anti-inflammatory properties through modulation of secretion of both pro-inflammatory and anti-inflammatory cytokines from LPS-stimulated macrophages through distinct signaling cascades. Therapeutic utility of ghrelin to control, modulate, or treat pathologic inflammatory conditions like endotoxemic shock and ulcerative colitis requires additional investigation.

 

[BiggerStronger]

Myostatin Propeptide Gene Delivery by Adeno-Associated Virus Serotype 8 Vectors Enhances Muscle Growth and Ameliorates Dystrophic Phenotypes in mdx Mice.
Qiao C, Li J, Jiang J, Zhu X, Wang B, Li J, Xiao X.

Division of Molecular Pharmaceutics, University of North Carolina School of Pharmacy, Chapel Hill, NC 27599.

Myostatin has been extensively documented as a negative regulator of muscle growth. Myostatin inhibition is therefore considered an attractive strategy for the treatment of muscle-wasting diseases such as muscular dystrophies. To investigate whether systemic gene delivery of myostatin propeptide (MRPO), a natural inhibitor of myostatin, could enhance body-wide skeletal muscle growth, we used adeno-associated virus serotype 8 (AAV8) vectors to deliver the MRPO gene into either normal mice or mdx mice, a murine model of Duchenne muscular dystrophy (DMD). In normal mice, a significant increase in skeletal muscle mass was observed after either an intraperitoneal injection of AAV-MPRO into neonates, or an intravenous injection of AAV-MPRO76AFc (a modified MPRO fused with IgG Fc) into adults. Enhanced muscle growth occurred because of myofiber hypertrophy, not hyperplasia. In mdx mice, a significant increase in skeletal muscle mass was also observed after AAV-MPRO76AFc injection. The treated mdx mice showed larger and more uniform myofibers, fewer infiltrating mononuclear cells, less fibrosis, and lower serum creatine kinase levels. In addition, a grip force test and an in vitro tetanic contractile force test showed improved muscle strength. A treadmill test, however, showed reduced endurance of the treated mdx mice compared with their untreated counterparts. Importantly, no cardiac hypertrophy was observed in either normal or mdx mice after myostatin inhibition by gene delivery. These results clearly demonstrate the efficacy of AAV8-mediated myostatin propeptide gene delivery in a rodent model of DMD, and warrant further investigation in large animal models and eventually in human patients.

 

[saudades]

Now the second one I'm really interested in. Not to mention that some of these companies that sell peptides also sell follistatin which is known to inhibit myostatin. I've been thinking of trying to get my hands on some.

 

[BiggerStronger]

DO NOT USE FOLLISTATIN

Sorry for the all caps but follistatin binds to other TGF ligands that control bodily functions and even more important curbing cell growth aka "malignant/benign cell growth" aka possible cancer or tumors. If you are looking for a myostatin binder look for GASP-1. It is a follistatin derivative and it only binds to GDF-8 (myostatin).

Now I have heard of people using follistatin but in the interest of harm reduction I've got to warn you that it is unknown what could happen if you are pre-disposed to having cancer or a small tumor that may have otherwise laid dormant.

 

[BiggerStronger]

Regulation of myostatin in vivo by growth and differentiation factor-associated serum protein-1: a novel protein with protease inhibitor and follistatin domains.
Hill JJ, Qiu Y, Hewick RM, Wolfman NM.

Department of Protein Chemistry and Proteomics, Wyeth Research, 200 Cambridge Park Drive, Cambridge, Massachusetts 02140, USA. [email protected].

Myostatin, a member of the TGFbeta superfamily, is a potent and specific negative regulator of skeletal muscle mass. In serum, myostatin circulates as part of a latent complex containing myostatin propeptide and/or follistatin-related gene (FLRG). Here, we report the identification of an additional protein associated with endogenous myostatin in normal mouse and human serum, discovered by affinity purification and mass spectrometry. This protein, which we have named growth and differentiation factor-associated serum protein-1 (GASP-1), contains multiple domains associated with protease-inhibitory proteins, including a whey acidic protein domain, a Kazal domain, two Kunitz domains, and a netrin domain. GASP-1 also contains a domain homologous to the 10-cysteine repeat found in follistatin, a protein that binds and inhibits activin, another member of the TGFbeta superfamily. We have cloned mouse GASP-1 and shown that it inhibits the biological activity of mature myostatin, but not activin, in a luciferase reporter gene assay. Surprisingly, recombinant GASP-1 binds directly not only to mature myostatin, but also to the myostatin propeptide. Thus, GASP-1 represents a novel class of inhibitory TGFbeta binding proteins.

 

[BiggerStronger]

If anyone has any direct experience with follistatin please share. I had a article I wrote a long time ago that listed a lot of info about myostatin and it's binders. I need to dig it up. If I remember correctly there were some serious issues with follistatin, but it may be an in-vitro function instead of in-vivo. I would love to hear more on the subject.

 

[saudades]

The same companies probably also sell gasp-1. I don't remember seeing any info that said follistatin was bad. The mice in the experiment had no bad side effects. That would be great if you can find that info on follistatin. In the mean time I'll think about gasp-1.

 

[BiggerStronger]

Let me know what you find out bud...

 

[saudades]

Looks like it is still too expensive. 25 ug (nanograms) for $315 is too pricey for me.

 

[BiggerStronger]

Yeah, most research outfits are going to be expensive. Try looking for lower grade peptides. Usually not too much of a difference in quality (slight purity level differences) but the price is way cheaper. I'll see if I can look around. You would need many times that amount to get any effect. 25ug is a very very small amount.

 

[BiggerStronger]

Transgenic expression of a myostatin inhibitor derived from follistatin increases skeletal muscle mass and ameliorates dystrophic pathology in mdx mice.Nakatani M, Takehara Y, Sugino H, Matsumoto M, Hashimoto O, Hasegawa Y, Murakami T, Uezumi A, Takeda S, Noji S, Sunada Y, Tsuchida K.
Division for Therapies Against Intractable Diseases, Institute for Comprehensive Medical Sciences (ICMS), Fujita Health University, Toyoake, Aichi 470-1192, Japan.

Myostatin is a potent negative regulator of skeletal muscle growth. Therefore, myostatin inhibition offers a novel therapeutic strategy for muscular dystrophy by restoring skeletal muscle mass and suppressing the progression of muscle degeneration. The known myostatin inhibitors include myostatin propeptide, follistatin, follistatin-related proteins, and myostatin antibodies. Although follistatin shows potent myostatin-inhibiting activities, it also acts as an efficient inhibitor of activins. Because activins are involved in multiple functions in various organs, their blockade by follistatin would affect multiple tissues other than skeletal muscles. In the present study, we report the characterization of a myostatin inhibitor derived from follistatin, which does not affect activin signaling. The dissociation constants (K(d)) of follistatin to activin and myostatin are 1.72 nM and 12.3 nM, respectively. By contrast, the dissociation constants (K(d)) of a follistatin-derived myostatin inhibitor, designated FS I-I, to activin and myostatin are 64.3 microM and 46.8 nM, respectively. Transgenic mice expressing FS I-I, under the control of a skeletal muscle-specific promoter showed increased skeletal muscle mass and strength. Hyperplasia and hypertrophy were both observed. We crossed FS I-I transgenic mice with mdx mice, a model for Duchenne muscular dystrophy. Notably, the skeletal muscles in the mdx/FS I-I mice showed enlargement and reduced cell infiltration. Muscle strength is also recovered in the mdx/FS I-I mice. These results indicate that myostatin blockade by FS I-I has a therapeutic potential for muscular dystrophy.

 

[BiggerStronger]

1: Rinsho Shinkeigaku. 2006 Nov;46(11):942-4.Links
[Therapeutic strategies for muscular dystrophy by myostatin inhibition][Article in Japanese]


Sunada Y.
Department of Neurology, Kawasaki Medical School.

Myostatin is a member of the TGF-beta superfamily that is expressed predominantly in skeletal muscle and functions as a negative regulator of skeletal muscle mass. Myostatin inhibition, therefore, has tremendous potential for increasing muscle mass clinically to treat patients with muscle wasting diseases. Systemic administration of a myostatin neutralizing antibody in mdx mice (a model of Duchenne muscular dystrophy) resulted in an increase in skeletal muscle mass and strength. A human anti-myostatin monoclonal antibody, MYO-029 is under clinical trials in patients with muscular dystrophy in the USA and Europe. Additional approaches to myostatin inhibition have been shown to have beneficial effects in vivo. Blockade of myostatin activity with the myostatin prodomain resulted in increases in muscle mass, enhanced muscle function, and histological improvement of the dystrophic muscle in mdx mice and mutant caveolin-3 transgenic mice (a model of LGMD1C). Treatment with an extracellular ligand-binding domain of the myostatin receptor, ActRIIB, resulted in prominent muscle mass increases in LGMD1C model mice. These findings indicate that myostatin inhibition could lead to effective therapeutics to treat muscular dystrophy. However, therapeutic indication against various types of muscular dystrophy as well as safety of the treatment should be established for the future clinical application.

 

[BiggerStronger]

Myostatin does not regulate cardiac hypertrophy or fibrosis.Cohn RD, Liang HY, Shetty R, Abraham T, Wagner KR.
McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. [email protected]

Myostatin is a negative regulator of muscle growth. Loss of myostatin has been shown to cause increase in skeletal muscle size and improve skeletal muscle function and fibrosis in the dystrophin-deficient mdx muscular dystrophy mouse model. We evaluated whether lack of myostatin has an impact on cardiac muscle growth and fibrosis in vivo. Using genetically modified mice we assessed whether myostatin absence induces similar beneficial effects on cardiac function and fibrosis. Cardiac mass and ejection fraction were measured in wild-type, myostatin-null, mdx and double mutant mdx/myostatin-null mice by high resolution echocardiography. Heart mass, myocyte area and extent of cardiac fibrosis were determined post mortem. Myostatin-null mice do not demonstrate ventricular hypertrophy when compared to wild-type mice as shown by echocardiography (ventricular mass 0.69+/-0.01 vs. 0.69+/-0.018 g) and morphometric analyses including heart/body weight ratio (5.39+/-0.45 vs. 5.62+/-0.58 mg/g) and cardiomyocyte area 113.67+/-1.5, 116.85+/-1.9 microm(2)). Moreover, absence of myostatin does not attenuate cardiac fibrosis in the dystrophin-deficient mdx mouse (12.2% vs. 12%). The physiological role of myostatin in cardiac muscle appears significantly different than that in skeletal muscle as it does not induce cardiac hypertrophy and does not modulate cardiac fibrosis in mdx mice.

 

[BiggerStronger]

Postnatal expression of myostatin propeptide cDNA maintained high muscle growth and normal adipose tissue mass in transgenic mice fed a high-fat diet.Yang J, Zhao B.
Department of Human Nutrition, Food and Animal Sciences, University of Hawaii, Honolulu, HI 96822, USA. [email protected]

Myostatin plays a robust, negative role in controlling muscle mass. A disruption of myostatin function by transgenic expression of its propeptide (the 5'region, 866 nucleotides) results in significant muscle growth (Yang et al., 2001. Mol Rep Dev 60:351-361). Studies from myostatin and the propeptide transgene mRNA indicated that myostatin mRNA was detected at day 10.5 postcoitum in fetal mice. Its level remained low, but increased by 180% during the postnatal fast-growth period (day 0-10). An early, high-level postnatal expression of the transgene was identified as being responsible for a highly muscled phenotype. High-fat diet induces adiposity in rodents. To study the effects of dietary fat on muscle growth and adipose tissue fat deposition in the transgenic mice, we challenged the mice with a high-fat diet (45% kcal fat) for 21 weeks. Transgenic mice showed 24%-50% further enhancement of growth on the high-fat diet compared to the normal-fat diet (P = 0.004) from 17 to 25 weeks of age. The total mass of the main muscles of transgenic mice showed a 27% increase on the high-fat diet compared to the normal-fat diet (P = 0.004), while the white adipose tissue mass of the transgenic mice was not significantly different from that of wild-type mice fed a normal-fat diet (P = 0.434). The high-fat diet induced wild-type mice developed 190% greater mass of white adipose tissues compared to the normal-fat diet (P = 0.008), which primarily resulted from enlarged adipocytes. These results demonstrate that disruption of myostatin function by its propeptide shifted dietary fat utilization toward muscle tissues with minimal effects on adiposity. These results suggest that enhancing muscle growth by myostatin propeptide or other means during the early developmental stage may serve as an effective means for obesity prevention. Copyright 2006 Wiley-Liss, Inc.

PMID: 16437538 [PubMed - indexed for MEDLINE]

 

[saudades]

Very interesting stuff....I understand the follistatin problem now. Thanks for posting that.

 

[BiggerStronger]

No problem bud...

Looking at this material it appears that the myostatin propeptide might be a viable option perhaps better than GASP-1 if I am reading this correctly.

 

[saudades]

Yeah, that's what I am understanding, too.

 

[saudades]

Whoa, I found a company selling myostatin propeptide, but it was 1mg for $7,920!

We need to make this stuff mainstream so the price will come down.

 

[BiggerStronger]

I remember someone selling myo-29 (i think at least) which was one of the trial drugs (for MD) for a semi-reasonable price. I think it was close to 2k for enough for a cycle of it. It was a research chemical store, but I can't remember the name. Still 2k is a ton of money and even worse close to $8000 to be a guinea pig is a lot to put out.

I agree I hope that this goes mainstream a bit so it's at least affordable. If it's worthwhile it will. Remember when IGF cost 1k to 2k+ per mg?

 

[BiggerStronger]

I found the propeptide for $5200 for 1mg. I need to figure out dosing for this.