Background: Cerebral palsy (CP) associates cerebral function damages with strong locomotor defects and premature sarcopenia. We previously showed that fibroblast growth factor 19 (FGF19) exerts hypertrophic effects on skeletal muscle and improves muscle mass and strength in mouse models with muscle atrophy. Facing the lack of therapeutics to treat locomotor dysfunctions in CP, we investigated whether FGF19 treatment could have beneficial effects in an experimental rat model of CP.Methods: Cerebral palsy was induced in male Wistar rat pups by perinatal anoxia immediately after birth and by sensorimotor restriction of hind paws maintained until Day 28. Daily subcutaneous injections with recombinant human FGF19 (0.1 mg/kg bw) were performed from Days 22 to 28. Locomotor activity and muscle strength were assessed before and after FGF19 treatment. At Day 29, motor coordination on rotarod and various musculoskeletal parameters (weight of tibia bone and of soleus and extensor digitorum longus (EDL) muscles; area of skeletal muscle fibres) were evaluated. In addition, expression of specific genes linked to human CP was measured in rat skeletal muscles.Results: Compared to controls, CP rats had reduced locomotion activity (−37.8% of distance travelled, P < 0.05), motor coordination (−88.9% latency of falls on rotarod, P < 0.05) and muscle strength (−25.1%, P < 0.05). These defects were associated with reduction in soleus (−51.5%, P < 0.05) and EDL (−42.5%, P < 0.05) weight, smaller area of muscle fibres, and with lower tibia weight (−38%, P < 0.05). In muscles from rats submitted to CP, changes in the expression levels of several genes related to muscle development and neuromuscular junctions were similar to those found in wrist muscle of children with CP (increased mRNA levels of Igfbp5, Kcnn3, Gdf8, and MyH4 and decreased expression of Myog, Ucp2 and Lpl). Compared with vehicle‐treated CP rats, FGF19 administration improved locomotor activity (+53.2%, P < 0.05) and muscle strength (+25.7%, P < 0.05), and increased tibia weight (+13.8%, P < 0.05) and soleus and EDL muscle weight (+28.6% and +27.3%, respectively, P < 0.05). In addition, it reduced a number of very small fibres in both muscles (P < 0.05). Finally, gene expression analyses revealed that FGF19 might counteract the immature state of skeletal muscles induced by CP.Conclusions: These results demonstrate that pharmacological intervention with recombinant FGF19 could restore musculoskeletal and locomotor dysfunction in an experimental CP model, suggesting that FGF19 may represent a potential therapeutic strategy to combat the locomotor disorders associated with CP.

Renal ischemia-reperfusion (IR) injury can lead to acute kidney injury, increasing the risk of developing chronic kidney disease. We hypothesized that mild therapeutic hypothermia (mTH), 34 °C, applied during ischemia could protect the function and structure of kidneys against IR injuries in mice. In vivo bilateral renal IR led to an increase in plasma urea and acute tubular necrosis at 24 h prevented by mTH. One month after unilateral IR, kidney atrophy and fibrosis were reduced by mTH. Evaluation of mitochondrial function showed that mTH protected against IR-mediated mitochondrial dysfunction at 24 h, by preserving CRC and OX-PHOS. mTH completely abrogated the IR increase of plasmatic IL-6 and IL-10 at 24 h. Acute tissue inflammation was decreased by mTH (IL-6 and IL1-β) in as little as 2 h. Concomitantly, mTH increased TNF-α expression at 24 h. One month after IR, mTH increased TNF-α mRNA expression, and it decreased TGF-β mRNA expression. We showed that mTH alleviates renal dysfunction and damage through a preservation of mitochondrial function and a modulated systemic and local inflammatory response at the acute phase (2–24 h). The protective effect of mTH is maintained in the long term (1 month), as it diminished renal atrophy and fibrosis, and mitigated chronic renal inflammation.

The adaptive response to overfeeding is associated with profound modifications of gene expression in adipose tissue to support lipid storage and weight gain. The objective of this study was to assess in healthy lean men whether a supplementation with polyphenols could interact with these molecular adaptations. Abdominal subcutaneous adipose tissue biopsies were sampled from 42 subjects participating to an overfeeding protocol providing an excess of 50% of their total energy expenditure for 31 days, and who were supplemented with 2 g/day of grape polyphenols or a placebo. Gene expression profiling was performed by RNA sequencing. Overfeeding led to a modification of the expression of 163 and 352 genes in the placebo and polyphenol groups, respectively. The GO functions of these genes were mostly involved in lipid metabolism, followed by genes involved in adipose tissue remodeling and expansion. In response to overfeeding, 812 genes were differentially regulated between groups. Among them, a set of 41 genes were related to angiogenesis and were down-regulated in the polyphenol group. Immunohistochemistry targeting PECAM1, as endothelial cell marker, confirmed reduced angiogenesis in this group. Finally, quercetin and isorhamnetin, two polyphenol species enriched in the plasma of the volunteers submitted to the polyphenols, were found to inhibit human umbilical vein endothelial cells migration in vitro. Polyphenol supplementation do not prevent the regulation of genes related to lipid metabolism in human adipose tissue during overfeeding, but impact the angiogenesis pathways. This may potentially contribute to a protection against adipose tissue expansion during dynamic phase of weight gain.

Abetalipoproteinemia (FHBL-SD1) and chylomicron retention disease (FHBL-SD3) are rare recessive disorders of lipoprotein metabolism due to mutations in MTTP and SAR1B genes, respectively, which lead to defective chylomicron formation and secretion. This results in lipid and fat-soluble vitamin malabsorption, which induces severe neuro-ophthalmic complications. Currently, treatment combines a low-fat diet with high-dose vitamin A and E supplementation but still fails in normalizing serum vitamin E levels and providing complete ophthalmic protection. To explore these persistent complications, we developed two knock-out cell models of FHBL-SD1 and FHBL-SD3 using the CRISPR/Cas9 technique in Caco-2/TC7 cells. DNA sequencing, RNA quantification and Western blotting confirmed the introduction of mutations with protein knock-out in four clones associated with i) impaired lipid droplet formation and ii) defective triglyceride (−57.0 ± 2.6% to −83.9 ± 1.6%) and cholesterol (−35.3 ± 4.4% to −60.6 ± 3.5%) secretion. A significant decrease in α-tocopherol secretion was also observed in these clones (−41.5 ± 3.7% to −97.2 ± 2.8%), even with the pharmaceutical forms of vitamin E: tocopherol-acetate and tocofersolan (α-tocopheryl polyethylene glycol succinate 1000). MTTP silencing led to a more severe phenotype than SAR1B silencing, which is consistent with clinical observations. Our cellular models thus provide an efficient tool to experiment with therapeutic strategies and will allow progress in understanding the mechanisms involved in lipid metabolism.

Aims/hypothesis: Postprandial glucagon-like peptide-1 (GLP-1) secretion by enteroendocrine L cells of the gut plays an important role in glucose homeostasis, thus representing a therapeutic option of ever-growing significance for type 2 diabetes. However, the precise mechanisms linking nutrient sensing and GLP-1 secretion are incompletely understood. In this study, we focused on a potential new role for endoplasmic reticulum (ER)–mitochondria contact sites, called mitochondria-associated membranes (MAMs), in nutrient-induced GLP-1 secretion by L cells, as they are dynamically regulated by nutrients, they influence cellular calcium homeostasis crucial for hormone secretion, and their miscommunication has been implicated in alterations of glucose homeostasis in several tissues. Methods: We combined biochemical and imaging approaches to investigate nutrient-induced GLP-1 secretion, and ER–mitochondria interaction and calcium exchange in the STC-1 cell line, ex vivo ileal mouse organoids, and/or in vivo in gut enteroendocrine cells from Glu-Venus mice, both in acute conditions and after diet-induced obesity and type 2 diabetes. Results: We show here that ER–mitochondria interactions are dynamically induced by two GLP-1 secretagogues, glucose and deoxycholic acid (DCA), in STC-1 cells (1.8- and 2.1-fold, respectively), ileal mouse organoids (1.7- and 1.3-fold, respectively), and in vivo in colonic L cells of Glu-Venus mice (1.3- and 1.2-fold, respectively). In addition, glucose increased ER–mitochondria calcium exchange in STC-1 cells (1.2-fold). A paracrine action of secreted GLP-1 was also involved in the regulation of MAMs by glucose and DCA in STC-1 cells. Dynamic reinforcement of MAMs by glucose and DCA played a causal role in GLP-1 release, as both pharmacological and genetic disruption of organelle communication blocked L cell secretory response to the two stimuli in STC-1 cells. In agreement, depleting ER calcium levels or inhibiting mitochondrial calcium entry decreased glucose-induced GLP-1 secretion (−37.5% and −30.9%, respectively), whereas inducing ER or mitochondrial stress prevented it (−47.9% and −51.8%, respectively). Mechanistically, glucose induces ER–mitochondria communication through a sodium–glucose cotransporter 1-mediated electrogenic effect, whereas DCA acts through a Takeda G protein-coupled receptor 5 (TGR5)–cAMP–protein kinase A (PKA) pathway. Finally, we demonstrated in C57Bl/6J mice and in Glu-Venus mice that diet-induced obesity reinforced basal ER–mitochondria interactions in colonic L cells and blocked their ability to respond to oral glucose in terms of both GLP-1 secretion and MAM upregulation. Conclusions/interpretation: These results point to a new role for ER–mitochondria calcium coupling in glucose-induced GLP-1 secretion in L cells of the gut, which is impaired in obesity and type 2 diabetes, providing a novel target for the modulation of GLP-1 secretion. Therefore, these data reinforce the potential targeting of MAMs to improve glycaemic outcomes in metabolic diseases.