bims-stacyt Biomed news on
Starvation pathways leading to cytokine regulation
Issue of 2018‒01‒07
four papers selected by
Cristina Muñoz Pinedo
L’Institut d’Investigació Biomèdica de Bellvitge

  1. Metabolism. 2017 Dec 28. doi: 10.1016/j.metabol.2017.12.008
    Abstract:  OBJECTIVE: Obese adipose tissue has been characterized with chronic inflammation associated with elevated secretion of inflammatory cytokines and declined secretion of anti-inflammatory cytokines which can impair endothelial function in an endocrine manner. Adipose tissue hypoxia plays a role in the changes of cytokines. Physical exercise / muscle contraction may help preventing cardiovascular disease through improving insulin resistance and endothelium function. However the mechanism is unclear. Skeletal muscle is an endocrine tissue. Contracting muscles secrete myokines which may play roles in the beneficial effect of exercise. In this study, the conditioned medium from electrical pulse stimulation (EPS) regulated skeletal muscle cells was used to explore the mechanism of contraction on endothelial dysfunction and insulin resistance induced by conditioned medium from hypoxic adipocytes. METHODS: 3T3-L1 adipocytes were incubated under normoxia or hypoxia condition, respectively. The supernatant was collected as adipocyte conditioned medium (CM-N and CM-H). C2C12 mouse skeletal muscle cells were stimulated with EPS for 12h. The supernatant was collected as muscle cells conditioned medium (CM-EPS). Human umbilical vein endothelial cells (HUVECs) were incubated with adipocyte CM and muscle cells CM together. Macrophages migration to HUVECs were detected with transwell system. The mRNA expressions of E-selectin, ICAM-1, MCP-1 and IL-6 were measured by real-time PCR. The phosphorylation of IKKα/β, NF-κB, Akt, AMPK, eNOS and SOCS3 protein levels were detected by Western blot. Concentration of NO was measured by ELISA kit. HUVECs apoptosis was detected by flow cytometry. RESULTS: CM-EPS reduced the increase of mRNA expressions of E-selectin, ICAM-1, MCP-1 and IL-6 in HUVECs induced by CN-H. The phosphorylations of IKKα/β and NF-κB, SOCS3 protein level and endothelial cells apoptosis, which were rised by CM-H, were significantly reduced by CM-EPS. CM-EPS reversed the effects of CM-H on Akt and eNOS phosphorylations and NO production in HUVECs. CM-EPS directly stimulated the phosphorylation of AMPK, which caused the following phosphorylation of eNOS in HUVECs. CONCLUSION: In summary, CM-EPS reversed endothelial cells inflammation, apoptosis, insulin resistance and dysfunction induced by CM-H.
    Keywords:  adipocytes; condition medium; contraction; electrical pulse stimulation; endothelial dysfunction; hypoxia; insulin resistance; skeletal muscle cells
  2. Cancer Chemother Pharmacol. 2017 Dec 30. doi: 10.1007/s00280-017-3503-6
    Abstract:  PURPOSE: Tumor cell resistance to platinum-based chemotherapeutic agents is one of the major hurdles to successful cancer treatment with these drugs, and is associated with alterations in tumor cell immune evasion and immunomodulatory properties. Immunocyte targeting is considered as a relevant approach to fight drug-resistant cancer. In this study, immunological hallmarks of cis-DDP-resistant Lewis lung carcinoma cells (LLC/R9) were investigated. METHODS: Immunological features of LLC/R9 cells cultured in vitro in normoxic and hypoxic conditions as well as of those that were grown in vivo were examined. The expression of immunologically relevant genes was evaluated by RT-PCR. Tumor cell susceptibility to the macrophage contact tumoricidal activity and NK-mediated cytolysis was investigated in MTT test. TNF-α-mediated tumor cell apoptosis as well as macrophage phagocytosis, oxidative metabolism, and CD206 expression after the treatment with conditioned media from normoxic and hypoxic tumor cells were studied by flow cytometry. Flow cytometry was also used to characterize dendritic cell maturity. RESULTS: When growing in vitro, LLC/R9 were characterized by slightly increased immunosuppressive cytokine gene expression. Transition to in vivo growth was associated with the enhancement of transcription of these genes in tumor cells. LLC/R9 cells had lowered sensitivity to contact-dependent macrophage-mediated cytotoxicity and to the TNFα-mediated apoptosis in vitro. Conditioned media from hypoxic LLC/R9 cells stimulated reactive oxygen species generation and CD206 expression in non-sensitized macrophages. Acquisition of drug resistance by LLC/R9 cells was associated with their increased sensitivity to NK-cell-mediated cytolysis. Meanwhile, the treatment of LLCR/9-bearing animals with generated ex vivo and loaded with LLC/R9 cell-lysate dendritic cells (DCs) resulted in profoundly enhanced tumor metastasizing. CONCLUSION: Decreased sensitivity to macrophage cytolysis, polarizing effect on DCs maturation along with increased susceptibility to NK-cell cytotoxic action promote extensive local growth of chemoresistant LLC/R9 tumors in vivo, but hamper their metastasizing.
    Keywords:  Chemoresistance; Dendritic cells; Lewis lung carcinoma; Macrophage-mediated cytotoxicity; NK-cell-mediated cytolysis; cis-DDP
  3. Semin Immunol. 2017 Dec 27. doi: 10.1016/j.smim.2017.12.003
    Abstract:  Mesenchymal stem cells (MSCs) are a major component of the tumor microenvironment (TME) and play a key role in promoting tumor progression. The tumor uses exosomes to co-opt MSCs and re-program their functional profile from normally trophic to pro-tumorigenic. These tumor-derived small vesicles called "TEX" carry and deliver a cargo rich in proteins and nucleic acids to MSCs. Upon interactions with surface receptors on MSCs and uptake of the exosome cargo by MSCs, molecular, transcriptional and translational changes occur that convert MSCs into producers of factors that are necessary for tumor growth and that also alter functions of non-tumor cells in the TME. The MSCs re-programmed by TEX become avid producers of their own exosomes that carry and deliver mRNA and miRNA species as well as molecular signals not only back to tumor cells, directly enhancing their growth, but also horizontally to fibroblasts, endothelial cells and immune cells in the TME, indirectly enhancing their pro-tumor functions. TEX-driven cross-talk of MSCs with immune cells blocks their anti-tumor activity and/or converts them into suppressor cells. MSCs re-programmed by TEX mediate pro-angiogenic activity and convert stromal cells into cancer-associated fibroblasts (CAFs). Although MSCs have a potential to exert anti-tumor activities, they largely provide service to the tumor using the multidirectional communication system established by exosomes in the TME. Future therapeutic options consider disruption of this complex vicious cycle by either molecular or gene-regulated silencing of pro-tumor effects mediated by MSCs in the TME.
    Keywords:  Immune modulation in the TME; MSC-derived exosomes; Mesenchymal stem cells (MSCs); TEX-driven re-programming; Tumor microenvironment (TME); Tumor-derived exosomes (TEX)
  4. Trends Endocrinol Metab. 2017 Dec 28. doi: 10.1016/j.tem.2017.11.008
    Abstract:  Over the past years, basic findings in cancer research have revealed metabolic symbiosis between different cell types to cope with high energy demands under limited nutrient availability. Although this also applies to regenerating tissues with disrupted physiological nutrient and oxygen supply, the impact of this metabolic cooperation and metabolic reprogramming on cellular development, fate, and function during tissue regeneration has widely been neglected so far. With this review, we aim to provide a schematic overview on metabolic links that have a high potential to drive tissue regeneration. As bone is, aside from liver, the only tissue that can regenerate without excessive scar tissue formation, we will use bone healing as an exemplarily model system.
    Keywords:  bone regeneration; fracture; inflammation; lactate; mesenchymal stromal cells; metabolism