Saturday, March 14, 2009


 Hiroki Yokota participated in this study.

Salubrinal Reduces Expression and Activity of MMP13 in Chondrocytes.

"Stress to the endoplasmic reticulum (ER) and inflammatory cytokines induce expression and activity of matrix metalloproteinase 13 (MMP13). Since a synthetic agent, salubrinal, is known to alleviate ER stress and attenuate nuclear factor kappa B (NFκB) signaling, we addressed a question whether upregulation of MMP13 by ER stress and cytokines is suppressed by administration of salubrinal.
Using C28/I2 human chondrocytes, we applied ER stress with tunicamycin and inflammatory distress with tumor necrosis factor α (TNFα) and interleukin 1β (IL1β). RNA interference with siRNA specific to NFκB p65 (RelA) was employed to examine a potential involvement of NFκB signaling in salubrinal's action in regulation of MMP13. We also employed primary human chondrocytes and evaluated MMP13 activity.
Tunicamycin activated p38 MAPK, while inflammatory cytokines activated p38 MAPK and NFκB. In both cases, salubrinal significantly reduced expression and activity of MMP13. Silencing NFκB reduced inflammatory cytokine-driven upregulation of MMP13 activity.
Salubrinal downregulates expression and activity MMP13 through p38 and NFκB signaling."

Now MMP13 is actually essentially for endochondral ossification.

"elevation of the level of phosphorylated eIF2a leads to expression of activating transcription factor 4 (ATF4)"<-salubrinal inhibits EIF2a dephosphorylation.

"In response to 10 ng/ml IL1b and 1 mg/ml tunicamycin, the mRNA levels of MMP1, MMP2{up}, and MMP14{up} were not altered, but the level of MMP3{up} mRNA was elevated"

"salubrinal decreased the level of p-IKK that was known to downregulate the NFkB inhibitor, IkB"

This study does present a clear linkage between Salubrinal and height but doesn't rule out increase applications.

"Tunicamycin is an inhibitor of N-linked glycosylation and the formation of N-glycosidic protein-carbohydrate linkages"

"Tunicamycin increased the level of eIF2a phosphorylation (p-eIF2a) at 1 h, followed by an elevation in the level of ATF4 at 3 h"

"Co-incubation with tunicamycin and salubrinal presented an increase in p-eIF2a and ATF4"

"Tunicamycin induced phosphorylation of p38 MAPK (p-p38 MAPK) at 1 and 2 h, while administration of 10 mM salubrinal suppressed the tunicamycin-induced increase in p-p38 MAPK"  Tunicaymin did not activate NFkB.

The following article is by the LSJL lab:

Effects of salubrinal on development of osteoclasts and osteoblasts from bone marrow-derived cells.

"Osteoporosis is a skeletal disease leading to an increased risk of bone fracture. Using a mouse osteoporosis model induced by administration of a receptor activator of nuclear factor kappa-B ligand (RANKL), salubrinal was recently reported as a potential therapeutic agent. To evaluate the role of salubrinal in cellular fates as well as migratory and adhesive functions of osteoclast/osteoblast precursors, we examined the development of primary bone marrow-derived cells in the presence and absence of salubrinal{so we can see any potential effects of BM-MSCs on salubrinal for LSJL}.
Using the RANKL-injected and control mice, bone marrow-derived cells were harvested. Osteoclastogenesis was induced by macrophage-colony stimulating factor and RANKL, while osteoblastogenesis was driven by dexamethasone, ascorbic acid, and beta-glycerophosphate.
Salubrinal suppressed the numbers of colony forming-unit (CFU)-granulocyte/macrophages and CFU-macrophages, as well as formation of mature osteoclasts in a dosage-dependent manner. Salubrinal also suppressed migration and adhesion of pre-osteoclasts and increased the number of CFU-osteoblasts. Salubrinal was more effective in exerting its effects in the cells isolated from the RANKL-injected mice than the control. Consistent with cellular fates and functions, salubrinal reduced the expression of nuclear factor of activated T cells c1 (NFATc1) as well as tartrate-resistant acid phosphatase.
Salubrinal exhibits significant inhibition of osteoclastogenesis as well as stimulation of osteoblastogenesis in bone marrow-derived cells, and its efficacy is enhanced in the cells harvested from the osteoporotic bone samples."

We need of Salubrinal's effects on MSC's pre-differentiation to see if it can have an impact on LSJL.

"Salubrinal is reported to attenuate molecular signaling mediated by nuclear factor kappa B (NFκB)"

"C57BL/6 female mice (7 weeks of age) were used"

"mRNA and  protein expression of NFATc1 is downregulated by salubrinal. NFATc1 is a member of the
NFAT transcription factor family and a master transcription factor for osteoclast development. NFATc1-deficient embryonic stem cells are unable to differentiate into osteoclasts"

"MafB (V-maf musculoaponeurotic fibrosarcoma oncogene homolog B), IRF8 (interferon regulatory factor 8), and Bcl6 (V cell lymphoma) have been mentioned as inhibitors of NFATc1"<-Salubrinal may act through these inhibitors and if it does in turn the effects of these inhibitors could have importance for LSJL.

The Protective Effects of Salubrinal on the Cartilage and Subchondral Bone of the Temporomandibular Joint under Various Compressive Mechanical Stimulations

"Excessive mechanical loads on the temporomandibular joint (TMJ) can cause mandibular cartilage degradation and subchondral bone erosion{so it's possible that salubrinal may have no impact on healthy bone}, but the treatment of these conditions remains challenging. Salubrinal, which target eukaryotic translation initiation factor 2 alpha, has been shown to have multiple beneficial effects on skeletal tissue. Here, we examined the effect of a Salubrinal injection on the mandibular cartilage and subchondral bone of the TMJ under various compressive stresses. We conducted in vivo analyses in rat models using various compressive stresses (40 g and 80 g), and we observed time-related degeneration and pathological changes in the cartilage and subchondral bone of the TMJ at days 1, 3 and 7 through histological measurements, subcellular observation, and changes in proliferation and apoptosis. After the Salubrinal injection, the thickness of the cartilage recovered, and the pathological change was alleviated. In the Salubrinal/light (Sal/light) compressive stress group, the drug altered the proliferation and apoptosis of chondrocytes most significantly at day 1. In the Salubrinal/heavy (Sal/heavy) compressive stress group, the drug increased the proliferation of chondrocytes most significantly at day 1 and reduced the apoptosis of chondrocytes most significantly at day 7. Salubrinal also increased the area of the bone trabeculae and suppressed inflammatory responses and pathological change in the subchondral bone of the TMJ. Together, these results indicate that the administration of Salubrinal reduces apoptosis and strengthens the proliferation of chondrocyte to varying degrees at days 1, 3 and 7 under various compressive mechanical stresses, both of which contribute to the recovery of cartilage thickness and the alleviation of pathological change. Salubrinal also suppresses inflammatory responses and pathological change in the subchondral bone of the TMJ."

Since salubrinal increased chondrocyte proliferation could it increase longitudinal bone growth?

"endoplasmic reticulum stress (ERS) regulates mechanical stress-induced cartilage thinning. Salubrinal, which is an inhibitor of ERS, can elevate the phosphorylation of eukaryotic translation initiation factor 2 alpha (eIF2α). Through eIF2α-mediated transcriptional and translational regulation, Salubrinal has been shown to have multiple beneficial effects on skeletal tissue. First, Salubrinal downregulates the expression and activity of Matrix Metallopeptidase 13 (MMP13), in chondrocytes, suggesting its potential use for protecting chondrocytes and treating degenerative diseases, such as osteoarthritis. Second, the elevated phosphorylation of eIF2α induced by Salubrinal could stimulate osteoblastogenesis and bone formation. Third, Salubrinal suppresses osteoclastogenesis, followed by bone resorption and protection"<-Could any of these things make you taller?  I'd say there'd have to be a study with salubrinal on longitudinal bone growth.

" Compared to the controls, the mandibular cartilage of the light compressive mechanical stress group thinned gradually, and the thickness of the mandibular cartilage reduced to 85% (P<0.05), 70% (P<0.05), and less than 60% (P<0.01) of that of the control group in the 1-, 3-, and 7-day subgroups, respectively. Degeneration was observed. More lacunas were located in the proliferative zone (1-day subgroup of the light compressive mechanical stress group). The chondrocytes in the proliferative zone penetrated into the hypertrophic zones"

If the Loading plus Salubrinal groups have thicker articular cartilage regions that could indicate that salubrinal could help people grow taller.

Here's the effects of loading on the subchondral bone:

"The compressive stresses caused noticeable degenerative changes, including irregular changes to the order and morphology of the bone trabeculae and pathologic changes and inflammation in the heavy compressive stress group. Resorption of the trabeculae is indicated (arrow) in the 1-day and 3-day light compressive subgroups. Vacuole and inflammatory cells are indicated (arrow) in the 7-day compressive subgroup. After the Salubrinal injection, the trabeculae widths recovered. Vacuoles were not observed, and the trabeculae were continuous. In addition, inflammatory cells decreased."<-compressive stress without salubrinal may be more beneficial for inducing growth changes in the subchondral bone as degradation of bone is needed to induce height growth.

"In the heavy compressive mechanical stress group, the trabeculae resorbed extensively. The pathologic changes were most significant in the 7-day subgroup and took the form of fractures, vacuole and inflammatory cell infiltration. After the Salubrinal injection, the disorder of the bone trabeculae abated and recovered. Continuous trabeculae and alleviated inflammation could be observed. Fractures and vacuole disappeared."

Salubrinal reduced the number of apoptotic cells due to compressive loads.

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