Il-15

[Titan1]

Does enyone have some info about IL-15?

[joevette]

There is a little bit of info on the board, try a search. I've never heard of any first hand experience, though. The stuff's pretty expensive, and so I've never heard of anyone even trying it.

[LL08]

Whats this stuff do, info anyone?

[Titan1]

Interleukin-15: a novel anabolic cytokine for skeletal muscle.

Quinn LS, Haugk KL, Grabstein KH.

Geriatric Research, Education, and Clinical Center, American Lake VA Medical Center, Tacoma, WA 98493, USA.

Interleukin-15 (IL-15) is a recently discovered growth factor which is highly expressed in skeletal muscle. In order to determine a functional role for IL-15 in skeletal myogenesis, the effects of IL-15 on myoblast proliferation and muscle-specific myosin heavy chain (MHC) expression were analyzed using the mouse C2 skeletal myogenic cell line and primary fetal bovine skeletal myogenic cultures. IL-15 had no effect on [3H]thymidine incorporation, nor on the rate of myoblast differentiation, assessed by anti-MHC immunocytochemical staining, in either type of culture. However, Western blot analyses revealed that IL-15 used at concentrations of 10 or 100 ng/ml increased MHC accumulation five-fold in C2 myoblast cultures and 2.5-fold in primary bovine myogenic cultures. Moreover, C2 myotubes formed in the presence of IL-15 appeared larger than controls. These findings indicate IL-15 can stimulate differentiated myocytes and muscle fibers to accumulate increased amounts of contractile proteins. Well-fused primary bovine myogenic cultures treated with the mitotic inhibitor aphidicolin, then administered IL-15 and/or the anabolic growth factor insulin -like growth factor-I (IGF-I), were analyzed for MHC accumulation using Western blots. IL-15 used at 10 ng/ml doubled MHC accumulation and was as effective as IGF-I used at 10 or 100 ng/ml. IL-15 and IGF-I used together increased MHC accumulation close to five-fold, indicating these two factors can act additively on muscle fibers. These findings indicate IL-15 affects parameters associated with skeletal muscle fiber hypertrophy, and suggest that IL-15 may be a novel anabolic agent to increase skeletal muscle mass.

PMID: 7628408 [PubMed - indexed for MEDLINE]
(*)

Association of interleukin-15 protein and interleukin-15 receptor genetic variation with resistance exercise training responses.

Riechman SE, Balasekaran G, Roth SM, Ferrell RE.

Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, PA 15260, USA. [email protected]

Interleukin-15 (IL-15) is an anabolic cytokine that is produced in skeletal muscle and directly affects muscle anabolism in animal and in vitro models. The contribution of IL-15 variability in muscle responses to 10 wk of resistance exercise training in young men and women was examined by measuring acute and chronic changes in IL-15 protein in plasma and characterizing genetic variation in the IL-15 receptor-alpha gene (IL15RA). Participants trained 3 days a week at 75% of one repetition maximum, performing three sets (6-10 repetitions) of 13 resistance exercises. Plasma IL-15 protein was significantly increased (P < 0.05) immediately after acute resistance exercise but did not change with training and was not associated with variability in muscle responses with training. A single nucleotide polymorphism in exon 7 of IL15RA was strongly associated with muscle hypertrophy and accounted for 7.1% of the variation in regression modeling. A polymorphism in exon 4 was also independently associated with muscle hypertrophy and accounted for an additional 3.5% of the variation in hypertrophy. These results suggest that IL-15 is an important mediator of muscle mass response to resistance exercise training in humans and that genetic variation in IL15RA accounts for a significant proportion of the variability in this response.

PMID: 15531573 [PubMed - in process]

Overexpression of interleukin-15 induces skeletal muscle hypertrophy in vitro: implications for treatment of muscle wasting disorders.

Quinn LS, Anderson BG, Drivdahl RH, Alvarez B, Argiles JM.

Division of Gerontology and Geriatric Medicine, University of Washington, Seattle 98195, USA. [email protected]

Interleukin-15 (IL-15) is a novel anabolic factor for skeletal muscle which inhibits muscle wasting associated with cancer (cachexia) in a rat model. To develop a cell culture system in which the mechanism of the anabolic action of IL-15 on skeletal muscle could be examined, the mouse C2 skeletal myogenic cell line was transduced with a retroviral expression vector for IL-15 and compared to sister cells transduced with a control vector. Overexpression of IL-15 induced fivefold higher levels of sarcomeric myosin heavy chain and alpha-actin accumulation in differentiated myotubes. Secreted factors from IL-15-overexpressing myogenic cells, but not from control cells, induced increased myofibrillar protein accumulation in cocultured control myotubes. IL-15 overexpression induced a hypertrophic myotube morphology similar to that described for cultured myotubes which overexpressed the well-characterized anabolic factor insulin-like growth factor-I (IGF-I). However, in contrast to IGF-I, the hypertrophic action of IL-15 on skeletal myogenic cells did not involve stimulation of skeletal myoblast proliferation or differentiation. IL-15 induced myotube hypertrophy at both low and high IGF-I concentrations. Furthermore, in contrast to IGF-I, which stimulated only protein synthesis under these culture conditions, IL-15 both stimulated protein synthesis and inhibited protein degradation in cultured skeletal myotubes. These findings indicate that IL-15 action on skeletal myogenic cells is distinct from that of IGF-I. Due to the ability of IGF-I to stimulate cell division and its association with several forms of cancer, controversy exists concerning the advisability of treating cachexia or age-associated muscle wasting with IGF-I. Administration of IL-15 or modulation of the IL-15 signaling pathway may represent an alternative strategy for maintaining skeletal muscle mass under these conditions.

PMID: 12372339 [PubMed - indexed for MEDLINE]

(* You can get the full text of this which is very interesting. Look at the graph when stacked with IGF-1. From the conclusions:
"The precise roles, mode of action, and regulation of expression of IL15 in skeletal muscle tissue remain to be defiid Unlike other anabolic agents such as anabolic steroids , GH, or IGF, which have multiple effects on a wide range of tissues, the effects of IL15 may be more tissue-specific. IL15 may therefore prove to be a useful agent for stimulating skeletal muscle growth or reversing skeletal muscle atrophy.")