Randomized controlled study of the effect of a butter naturally enriched in trans fatty acids on blood lipids in healthy women123

Background: Whereas the negative effect of consuming trans fatty acids found in partially hydrogenated vegetable oils on cardiovascular disease (CVD) risk is well established, the effect of trans fatty acids from ruminant sources (rTFAs) on CVD risk factors has not yet been established, particularly among women

Lumina

"LUMINA is a tribute to light, honoured not for what it enables us to do, but for what it is: a form of energy made up both of corpuscles - which give it the status of a substance or body - and waves, through which it is propagated." -- page 7

Expression of CCAAT/Enhancer Binding Protein Beta in Muscle Satellite Cells Inhibits Myogenesis in Cancer Cachexia.

Cancer cachexia is a paraneoplastic syndrome that causes profound weight loss and muscle mass atrophy and is estimated to be the cause of up to 30% of cancer deaths. Though the exact cause is unknown, patients with cancer cachexia have increased muscle protein catabolism. In healthy muscle, injury activates skeletal muscle stem cells, called satellite cells, to differentiate and promote regeneration. Here, we provide evidence that this mechanism is inhibited in cancer cachexia due to persistent expression of CCAAT/Enhancer Binding Protein beta (C/EBPβ) in muscle myoblasts. C/EBPβ is a bzip transcription factor that is expressed in muscle satellite cells and is normally downregulated upon differentiation. However, in myoblasts exposed to a cachectic milieu, C/EBPβ expression remains elevated, despite activation to differentiate, resulting in the inhibition of myogenin expression and myogenesis. In vivo, cancer cachexia results in increased number of Pax7+ cells that also express C/EBPβ and the inhibition of normal repair mechanisms. Loss of C/EBPβ expression in primary myoblasts rescues differentiation under cachectic conditions without restoring myotube size, indicating that C/EBPβ is an important inhibitor of myogenesis in cancer cachexia

Inhibition of myogenesis correlates with induction of C/EBPβ expression in myoblasts.

<p><b>(A)</b> Immunocytochemistry staining of myosin heavy chain expression in C2C12 myoblasts pre-treated with conditioned media from SKOV3 or PC-3 cells mixed 1:1 with fresh media, for 48hrs, and induced to differentiate for an additional 5 days. DAPI stains nuclei blue. <b>(B)</b> C2C12 cultures were induced to differentiate as in (A) and the differentiation and fusion indices were calculated as relative to SKOV3-treated cells. Actual values are shown in the respective bars. *p<0.05, n = 5. <b>(C)</b> C/EBPβ, and myogenic marker protein expression in C2C12 myoblasts treated as in (A). Cyclophilin B (CyPB) is shown as a loading control. <b>(D)</b> Immunocytochemistry staining of myosin heavy chain (MYH) expression in primary myoblasts pre-treated with conditioned media from SKOV3 or PC-3 cells mixed 1:1 with fresh media, for 48hrs, and induced to differentiate for an additional 48 hours in DMEM containing 10% horse serum. DAPI stains nuclei blue. <b>(E)</b> Primary myoblast cultures were induced to differentiate as in <b>(D)</b> and the differentiation and fusion indices were calculated as relative to SKOV3-treated cells. Actual values are shown in the respective bars. **p<0.01, n = 4. <b>(F)</b> Percentage of Pax7+ cells relative to total nuclei remaining in C2C12 cells cultured in conditioned medium and differentiated as in (D) as determined by immunocytochemistry. *p<0.05, n = 4. <b>(G)</b> C/EBPβ, and myogenic marker protein expression in primary myoblasts treated as in (D). Cyclophilin B (CyPB) is shown as a loading control.</p

Pre-treatment with conditioned media from a prostate tumor inhibits skeletal muscle differentiation and upregulates C/EBPβ expression.

<p><b>(A)</b> Schematic of the treatment procedure for the tissue culture model of cachexia. Conditioned media from PC-3 cells was mixed 1:1 with fresh media, and was added onto proliferating C2C12 myoblasts for 48 hours after which cells were induced to differentiate in fresh DMEM containing 2% horse serum for 5 days. <b>(B)</b> Immunocytochemistry staining for myosin heavy chain expression in C2C12 cultures treated with conditioned media from PC-3 or DU145 prostate cancers or unconditioned media (UM) as in (A). DAPI stains nuclei blue. <b>(C)</b> C2C12 cultures were induced to differentiate as in (A) and the fusion index (#myonuclei/myotube) and differentiation index (#myonuclei/# total nuclei) was calculated, and shown relative to UM. Actual values are shown in the bars. *p<0.05, n = 7. <b>(D)</b> Western blot analysis of C/EBPβ, Pax7, and MyoD expression in proliferating C2C12 cells on day 2 after incubation with conditioned medium. Actin is a loading control. <b>(E)</b> Western blot analysis of myogenic marker expression in differentiated C2C12 cells on day 7. Actin is a loading control. <b>(F)</b> qRT-PCR analysis of <i>Myod1</i>, <i>Myog</i> and neonatal myosin heavy chain (<i>Myh1</i>, <i>Myh2</i>, <i>Myh8</i>, <i>Myh13</i>) expression, shown relative to cells treated with unconditioned medium (UM) on day 7. *p<0.05, n = 4.</p

Conditioned medium from human cancers stimulate C/EBPβ expression in myoblasts.

<p><b>(A)</b> C2C12 myoblasts were incubated with conditioned medium from indicated human cancers or unconditioned medium (UM) mixed 1:1 with fresh myoblast medium for 48 hours. C/EBPβ expression was assessed by western blot. β-actin is a loading control. <b>(B)</b><i>Cebpb</i> mRNA expression in myoblasts treated with PC-3 medium or unconditioned medium for 48 hours. *p<0.05, n = 5. <b>(C)</b><i>Il1b</i> expression in SKOV3 and PC-3 cancer cells. *p<0.05, n = 5.</p

LLC tumor graft increases C/EBPβ expression in myoblasts and prevents myogenesis.

<p><b>(A)</b> 5x10⁵ Lewis Lung Carcinoma (LLC) cells or PBS (Sham) was injected into the flank of C57BL/6 mice and allowed to engraft for 3 weeks to induce cachexia. <b>(B)</b> Immunocytochemistry for myosin heavy chain expression in primary myoblasts isolated from sham-injected and LLC-injected mice and differentiated for 2 days. <b>(C)</b> Differentiation (DI) and fusion (FI) indices from cultures isolated and differentiated as in (B). *p<0.05, n = 5. <b>(D)</b> Western analysis of C/EBPβ and myogenic marker expression in cells isolated from healthy or cachectic mice as in (A) and after culture expansion for 5 days, differentiated for 2 days. Cyclophilin B (CyPB) is a loading control.</p

SOX7 Is Required for Muscle Satellite Cell Development and Maintenance

Satellite cells are skeletal-muscle-specific stem cells that are activated by injury to proliferate, differentiate, and fuse to enable repair. SOX7, a member of the SRY-related HMG-box family of transcription factors is expressed in quiescent satellite cells. To elucidate SOX7 function in skeletal muscle, we knocked down Sox7 expression in embryonic stem cells and primary myoblasts and generated a conditional knockout mouse in which Sox7 is excised in PAX3+ cells. Loss of Sox7 in embryonic stem cells reduced Pax3 and Pax7 expression. In vivo, conditional knockdown of Sox7 reduced the satellite cell population from birth, reduced myofiber caliber, and impaired regeneration after acute injury. Although Sox7-deficient primary myoblasts differentiated normally, impaired myoblast fusion and increased sensitivity to apoptosis in culture and in vivo were observed. Taken together, these results indicate that SOX7 is dispensable for myogenesis but is necessary to promote satellite cell development and survival