Follistatin-344 is a naturally occurring glycoprotein that is considered to be present in almost all tissue. It is considered an autocrine chemical, meaning that the cell produces a chemical messenger through a cell signal, which binds to its autocrine receptors, resulting in cell modification.(1) Follistatin naturally occurs in two isoforms, FST 317 and FST 344, each composed of 317 and 344 amino acids, respectively. These two isoforms may be produced through alternative splicing process of the mRNA.(2)
Follistatin-344 is a synthetic version of the endogenous Follistatin-344 protein isoform. Although the number of amino acids differs in Follistatin isoforms, at its core, the protein is composed of 63 amino acid residues along with three domains: FSD1, FSD2, and FSD3, with an identical structure in the synthetic peptide.(3)
Researchers posit that Follistatin’s primary potential may exist in activin binding action.(4) Follistatin has been suggested to have a collaborative role in reproductive functioning alongside other chemicals like activin and inhibins. Scientists posit that the ovarian follicle mainly releases activin to enhance the secretion of follicle-stimulating hormone. Follistatin may bind with activin and thereby attenuate its action by inhibiting the secretion of the FSH hormone.
While the origin and mechanism of the peptide hormone are not entirely understood, it has been suggested that Follistatin-344 is locally produced in the pituitary gland, gonads, testes, and ovaries. Additionally, Follistatin may be vastly distributed in various organs of the body and is also potentially present in blood circulation due to its secretion from the blood vessels.
Research and Clinical Studies
Follistatin-344 and Muscle Development
Myostatin is a protein considered to be synthesized by muscle cells, hindering muscle cell differentiation and growth. Myostatin protein belongs to the transforming growth factor-beta (TGF-beta) protein, which Follistatin may inhibit. During one 1997 study,(5) it was suggested that mice given Follistatin-344 exhibited reduced levels of myostatin, which might have led to the improved skeletal muscle mass with each mouse weighing 2 to 3 times more than usual.
In another study,(6) Follistatin-344 was induced in mice via a nanoparticle-mediated mode of delivery of mRNA in the liver. The researchers reported that the mRNA messenger appeared to stimulate the hepatic liver cells to naturally synthesize and secrete Follistatin. Results of this study suggested that the peptide mice, given this mRNA-containing nanoparticle, exhibited apparently increased serum levels of Follistatin within 3 days as compared to the levels in control mice. After 8 weeks of continuous peptide presentation, the lean muscle mass of the peptide mice was reportedly 10% more than the control mice.
Follistatin-344 and Carcinogenic Cells
It was suggested, through reverse transcription polymerase chain reaction study (RT-PCR), that Follistatin levels may fluctuate in breast cancer test models. One study(9) examined the available gene expression data of mice with breast cancer. In most cases, Follistatin was reportedly under-expressed in carcinogenic breast cells, possibly leading to the increased spread of cancer cells caused by activin proteins. As Follistatin is suggested to bind to and inhibit activin proteins, it was further posited by the researchers that restoring Follistatin in these mice might prevent the prognosis of activin-induced metastasis and improve overall survival.
Research suggests that bone morphogenic protein (BMP) is one of the causative factors in the transition of normal esophageal tissue to cancerous tissues. Experimental studies in Follistatin-344 suggest that the peptide may counteract acid reflux, thereby possibly preventing an over-activation of BMP and development of esophageal cancer.(10)
Follistatin-344 and Cell Proliferation
There is an odd contrast in the working of Follistatin: it may potentially inhibit metastasis, as well as possibly promote cell proliferation. This is why the peptide is researched in studies scrutinizing increased tumor growth (tumorigenesis) and metastasis.(12) Research has suggested that hepatocytes (i.e., liver cells) may require Follistatin to proliferate. When studied in experimental rats, it was reported by the researchers that the inactivation of activin by Follistatin-344 may be a precondition for cell proliferation to occur. They believed that there may be some energy exchange amongst the cells where the energy used for cell migration is shut off to switch with cellular growth and proliferation.
Follistatin-344 and Liver Protection
One study(14) was conducted to determine the potential of Follistatin on early liver fibrosis. In this study, rats were divided into one control group and one Follistatin presented group for a period of four weeks. Researchers reported that the peptide group showed a 32% decrease in liver fibrosis as compared to the control group. They further reported that hepatocytic apoptosis was decreased by almost 90% in the Follistatin mice.
Follistatin-344 and Hair Growth
Follistatin may exhibit wound healing potential via possible stimulation of interfollicular stem cells, which lead to increased hair growth. A clinical study was conducted where the potential of this synthetic protein formulation, Hair Stimulating Complex (HSC), were studied in subjects with hair loss.(14). 26 subjects were presented with the peptide for a period of 52 weeks. Histopathological evaluation of the tissues reportedly showed improved hair growth after 52 weeks as compared to the placebo subjects. Besides hair growth, researchers reported was also an improvement in hair thickness and density by almost 13%.
Follistatin-344 and Diabetic Mice Models
Research has suggested that when Follistatin-344 was presented to diabetic mice, it appeared to lead to overexpression of the protein in the pancreatic cells, resulting in increased pancreatic beta cell mass, reduced glucose level and overall reduction in diabetic symptoms.(15)
Follistatin-344 peptide is available for research and laboratory purposes only. Please review and adhere to our Terms and Conditions before ordering.
- Hiroyuki Kaneko, Handbook of Hormones, 2016. www.sciencedirect.com/topics/neuroscience/follistatin
- FST follistatin [Homo sapiens (human)]. https://www.ncbi.nlm.nih.gov/gene?Db=gene&Cmd=DetailsSearch&Term=10468
- Shi, L., Resaul, J., Owen, S., Ye, L., & Jiang, W. G. (2016). Clinical and Therapeutic Implications of Follistatin in Solid Tumours. Cancer genomics & proteomics, 13(6), 425–435. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5219916/
- Rodino-Klapac, L. R., Haidet, A. M., Kota, J., Handy, C., Kaspar, B. K., & Mendell, J. R. (2009). Inhibition of myostatin with emphasis on follistatin as a therapy for muscle disease. Muscle & nerve, 39(3), 283–296. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2717722/
- McPherron AC, Lawler AM, Lee SJ. Regulation of skeletal muscle mass in mice by a new TGF-beta superfamily member. Nature. 1997 May 1;387(6628):83-90. https://pubmed.ncbi.nlm.nih.gov/9139826/
- Schumann C, Nguyen DX, Norgard M, Bortnyak Y, Korzun T, Chan S, Lorenz AS, Moses AS, Albarqi HA, Wong L, Michaelis K, Zhu X, Alani AWG, Taratula OR, Krasnow S, Marks DL, Taratula O. Increasing lean muscle mass in mice via nanoparticle-mediated hepatic delivery of follistatin mRNA. Theranostics 2018; 8(19):5276-5288. doi:10.7150/thno.27847. https://www.thno.org/v08p5276.htm
- skenderian A, Liu N, Deng Q, Huang Y, Shen C, Palmieri K, Crooker R, Lundberg D, Kastrapeli N, Pescatore B, Romashko A, Dumas J, Comeau R, Norton A, Pan J, Rong H, Derakhchan K, Ehmann DE. Myostatin and activin blockade by engineered follistatin results in hypertrophy and improves dystrophic pathology in mdx mouse more than myostatin blockade alone. Skelet Muscle. 2018 Oct 27;8(1):34. https://pubmed.ncbi.nlm.nih.gov/30368252/
- Zabkiewicz C, Resaul J, Hargest R, Jiang WG, Ye L. Increased Expression of Follistatin in Breast Cancer Reduces Invasiveness and Clinically Correlates with Better Survival. Cancer Genomics Proteomics. 2017 Jul-Aug;14(4):241-251. https://pubmed.ncbi.nlm.nih.gov/28647698/
- Seachrist DD, Sizemore ST, Johnson E, Abdul-Karim FW, Weber Bonk KL, Keri RA. Follistatin is a metastasis suppressor in a mouse model of HER2-positive breast cancer. Breast Cancer Res. 2017 Jun 5;19(1):66. https://pubmed.ncbi.nlm.nih.gov/28583174/
- Lau MC, Ng KY, Wong TL, Tong M, Lee TK, Ming XY, Law S, Lee NP, Cheung AL, Qin YR, Chan KW, Ning W, Guan XY, Ma S. FSTL1 Promotes Metastasis and Chemoresistance in Esophageal Squamous Cell Carcinoma through NFκB-BMP Signaling Cross-talk. Cancer Res. 2017 Nov 1. https://pubmed.ncbi.nlm.nih.gov/28883005/
- Shi L, Resaul J, Owen S, Ye L, Jiang WG. Clinical and Therapeutic Implications of Follistatin in Solid Tumours. Cancer Genomics Proteomics. 2016 11-12;13(6):425-435. https://pubmed.ncbi.nlm.nih.gov/27807065/
- Ooe H, Chen Q, Kon J, Sasaki K, Miyoshi H, Ichinohe N, Tanimizu N, Mitaka T. Proliferation of rat small hepatocytes requires follistatin expression. J Cell Physiol. 2012 Jun;227(6):2363-70. https://pubmed.ncbi.nlm.nih.gov/21826650/
- Patella S, Phillips DJ, Tchongue J, de Kretser DM, Sievert W. Follistatin attenuates early liver fibrosis: effects on hepatic stellate cell activation and hepatocyte apoptosis. Am J Physiol Gastrointest Liver Physiol. 2006 Jan;290(1):G137-44. https://pubmed.ncbi.nlm.nih.gov/16123203/
- Zimber MP, Ziering C, Zeigler F, Hubka M, Mansbridge JN, Baumgartner M, Hubka K, Kellar R, Perez-Meza D, Sadick N, Naughton GK. Hair regrowth following a Wnt- and follistatin containing treatment: safety and efficacy in a first-in-man phase 1 clinical trial. J Drugs Dermatol. 2011 Nov;10(11):1308-12. https://pubmed.ncbi.nlm.nih.gov/22052313/
- Zhao C, Qiao C, Tang RH, Jiang J, Li J, Martin CB, Bulaklak K, Li J, Wang DW, Xiao X. Overcoming Insulin Insufficiency by Forced Follistatin Expression in β-cells of db/db Mice. Mol Ther. 2015 May;23(5):866-874. doi: 10.1038/mt.2015.29. Epub 2015 Feb 13. PMID: 25676679; PMCID: PMC4427879. https://pubmed.ncbi.nlm.nih.gov/25676679/
Dr. Marinov (MD, Ph.D.) is a researcher and chief assistant professor in Preventative Medicine & Public Health. Prior to his professorship, Dr. Marinov practiced preventative, evidence-based medicine with an emphasis on Nutrition and Dietetics. He is widely published in international peer-reviewed scientific journals and specializes in peptide therapy research.