Transcriptome profiling reveals stress-responsive gene networks in cattle muscles

International audienceIn meat-producing animals, preslaughter operations ( e.g ., transportation, mixing unfamiliar animals, food and water deprivation) may be a source of stress with detrimental effects on meat quality. The objective of this work was to study the effect of emotional and physical stress by comparing the transcriptomes of two muscles (M. longissimus thoracis, LT and M. semitendinosus, ST ) in Normand cows exposed to stress ( n = 16) vs . cows handled with limited stress ( n = 16). Using a microarray, we showed that exposure to stress resulted in differentially expressed genes (DEGs) in both muscles (62 DEGs in LT and 32 DEGs in ST, of which eight were common transcription factors (TFs)). Promoter analysis of the DEGs showed that 25 cis transcriptional modules were overrepresented, of which nine were detected in both muscles. Molecular interaction networks of the DEGs targeted by the most represented cis modules helped identify common regulators and common targets involved in the response to stress. They provided elements showing that the transcriptional response to stress is likely to (i) be controlled by regulators of energy metabolism, factors involved in the response to hypoxia, and inflammatory cytokines; and (ii) initiate metabolic processes, angiogenesis, corticosteroid response, immune system processes, and satellite cell activation/quiescence. The results of this study demonstrate that exposure to stress induced a core response to stress in both muscles, including changes in the expression of TFs. These factors could relay the physiological adaptive response of cattle muscles to cope with emotional and physical stress. The study provides information to further understand the consequences of these molecular processes on meat quality and find strategies to attenuate them

La sous-nutrition modifie la réponse métabolique à une épreuve inflammatoire mammaire et le transcriptome hépatique chez des vaches laitières en début de lactation

La sous-nutrition modifie la réponse métabolique à une épreuve inflammatoire mammaire et le transcriptome hépatique chez des vaches laitières en début de lactation. 23. Rencontres autour des Recherches sur les Ruminant

Adipocyte/breast cancer cell crosstalk in obesity interferes with the anti-proliferative efficacy of tamoxifen.

Obesity is a well-known risk factor of breast cancer in post-menopausal women that also correlates with a diminished therapeutic response. The influence of adipocytes and their secretome, i.e. adipokines, on the efficacy of hormone therapy has yet to be elucidated.We investigated, ex vivo, whether mature adipocytes, differentiated from adipose stem cells of normal-weight (MA20) or obese (MA30) women, and their secretions, were able to counteract the effects of tamoxifen (Tx) which is known to decrease neoplastic cell proliferation.In a tridimensional model and in a model of co-culture, the anti-proliferative effect of Tx on MCF-7 cancer cells was counteracted by MA30. These two models highlighted two different specific gene expression profiles for genes encoding cytokines or involved in angiogenesis based on the adipocyte microenvironment and the treatment. Thus it notably showed altered expression of genes such as TNFα that correlated with IL-6. In addition, leptin, IL-6 and TNFα, at concentrations reflecting plasma concentrations in obese patients, decreased the anti-proliferative efficacy of 4-hydroxytamoxifen (a major active metabolite of Tx).These findings bring insights on adipocytes and mammary cancer cell interactions in Tx therapy, particularly in overweight/obese people. Indeed, patient' adipokine status would give valuable information for developing individual strategies and avoid resistance to treatment

Tridimensional adipose mammary equivalent model.

<p>(A) Hematoxylin Phloxin Safran staining showed a pluristratified and differentiated epithelium on a connective underlying tissue made of fibroblasts surrounded by their ECM coloured in yellow in the porous scaffold. (B) Mature adipocytes were visible after Oil Red O staining coloring their vesicles in pink. (C) Ki67 immunohistochemical staining of the tridimensional adipose equivalent model using affinity-purified polyclonal biotinylated antibodies raised against Ki67 (Magnification: ×400). Positive staining appeared in brown. (D) Ki67 immunofluorescent staining of the tridimensional adipose equivalent model. Positive staining appeared in red. (E) Comparison of cellular proliferation in tridimensional adipose equivalent model with or without mature adipocytes and tamoxifen treatment.</p

Effects of Leptin, IL-6 and TNFα on MCF-7 cell proliferation after 4-OH-tamoxifen treatment.

<p>After adhesion, MCF-7 were treated with leptin (0; 10; 100 ng/mL) (A), IL-6 (0, 2.3; 83 pg/mL) (B), TNFα (0; 0.7; 12.5 pg/mL) (C) and with 12.5 μM of 4-OH-Tx. After 72h, cell proliferation was quantified using a resazurine test (Fluoroskan Ascent^® FL). Mean ± SEM, $ 4-OH-Tx +/- adipokine <i>vs</i> Control, ¤ 4-OH-Tx +/- adipokine <i>vs</i> 4-OH-Tx (n = 3, Student's t test).</p

qRT-PCR assays on 3D adipose equivalent model.

<p>qRT-PCR assays on 3D adipose equivalent model.</p

Effect of mature adipocytes, their secretions and Tamoxifen (Tx) on cell proliferation.

<p>(A) MCF-7 cells were co-cultured with MA obtained from women of normal weight (MA20), overweight (MA27) or obese (MA30) women and treated with Tx. (B) 184B5 cells were co-cultured with MA27 with or without Tx. For A) and B), the proliferation was quantified after 72h using a resazurine test (Fluoroskan Ascent^® FL). (C) MCF-7 and (D) 184B5 cells were also cultured with conditioned media from the culture of MA20 (CM20) and AM30 (CM30) with or without Tx treatment. Results were expressed as Mean ± SEM, ¤ MA <i>vs</i> Control, * Tx <i>vs</i> Control, § MA+Tx <i>vs</i> Tx; $ CM30 <i>vs</i> CM20, £ CM+Tx <i>vs</i> CM, # CM30+Tx <i>vs</i> CM20+Tx (n = 3, Student's t test).</p

Principal component analysis (PCA) to explore the relationships among genes on 3D adipose skin equivalent model.

<p>The expression of genes in MCF-7 mammary cell line co-cultured or not with mature adipocytes from women with a normal weight (MA20) or obese women (MA30) with or without tamoxifen treatment were analyzed by PCA. A first global PCA was carried out (A) followed by a second one taking into account the biological function of the different studied genes (B, C, D, E).</p