Navegando por Palavras-chave "Unfolded Protein Response"

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    O impacto da mutação no gene LIPL-5 sobre a expressão da enzima Lipase-like 4 e resposta ao estresse em Caenorhabditis elegans
    (Universidade Federal de São Paulo (UNIFESP), 2021) Assis, Carolina Gomes De [UNIFESP]; Cunha, Fernanda Marques Da [UNIFESP]; Universidade Federal de São Paulo
    Introduction: Mitochondria are important organelles for the organism, as they are involved in several physiological processes crucial to the maintenance of homeostasis. In a study conducted previously by our group, it was observed that C. elegans with a loss-of-function mutation for the enzyme Lipase-Like 5 (LIPL-5) presented lipid profile alterations including increased amounts of ceramides and mitochondrial signature lipids. It was also observed that the mitochondria of these mutants had improved oxidative capacity when compared to mitochondria from wild type animals. However, the mechanisms by which LIPL-5 deficiency modulates the mitochondrial phenotype are unknown. Objective: To investigate the impact of the lipl-5 gene mutation on the expression of the enzyme Lipase-Like 4 (LIPL-4) and on the unfolded protein response (UPR) in C. elegans. Methods: To analyze the cytoplasmic UPR, a reporter strain mutant for lipl-5 was generated by crossing. For mitochondrial UPR and endoplasmic reticulum UPR, the lipl-5 gene was silenced by RNAi in the respective reporter strains. The activation of stress responses was assessed by fluorescence microscopy followed by quantification. Silencing was confirmed by qPCR, a method that was also used to assess the impact of LIPL-5 deficiency on lipl-4 relative expression, under conditions of bacterial deprivation and ad libitum. Results: lipl-5 silencing in the reporter animals for mitochondrial UPR resulted in a significant increase in the mean fluorescence intensity, indicating activation of UPRmt. lipl-5 silencing in the reporter animals for endoplasmic reticulum UPR, by itself, did not cause UPRer activation in basal conditions, but it impaired its activation in response to tunicamycin (TM) treatment. lipl-5 gene mutation did not provoke a stress response in the cytoplasm under baseline conditions nor significantly affected the response of the animals when challenged with heat shock. Regarding the impact of LIPL-5 deficiency on lipl-4 expression, when evaluating the expression of lipl-4 and lipl-5 in wild type animals (WT), it was seen that both are expressed in response to bacterial deprivation, but with different expression profiles. When investigating lipl-4 expression in lipl-5 mutants, it was possible to observe that, after 6 hours of bacterial deprivation, relative levels of lipl- 4 in the mutant were considerably higher than in WT, but without significant difference after 24 h of starvation. There was also no difference in lipl-4 expression levels in lipl-5 animals in ad libitum condition compared to WT. Conclusions: LIPL- 5 deficiency per se activates mitochondrial UPR, and impairs the response to endoplasmic reticulum UPR induced by TM. The effect of the absence of LIPL-5 is specific since the cytoplasmic UPR is not affected by its deficiency. The lack of LIPL- 5 does not affect lipl-4 expression in control conditions, but induces an early and intense increase in the lipl-4 expression in response to bacterial deprivation. The effects of LIPL-5 deficiency on UPRmt, UPRer and lipl-4 expression may be involved in mitochondrial phenotype alterations previously reported in lipl-5 animals.
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    Sleep is not just for the brain: transcriptional responses to sleep in peripheral tissues
    (Biomed Central Ltd, 2013-05-30) Anafi, Ron C.; Pellegrino, Renata [UNIFESP]; Shockley, Keith R.; Romer, Micah; Tufik, Sergio [UNIFESP]; Pack, Allan I.; Univ Penn; Childrens Hosp Philadelphia; Universidade Federal de São Paulo (UNIFESP); NIEHS
    Background: Many have assumed that the primary function of sleep is for the brain. We evaluated the molecular consequences of sleep and sleep deprivation outside the brain, in heart and lung. Using microarrays we compared gene expression in tissue from sleeping and sleep deprived mice euthanized at the same diurnal times.Results: in each tissue, nearly two thousand genes demonstrated statistically significant differential expression as a function of sleep/wake behavioral state. To mitigate the influence of an artificial deprivation protocol, we identified a subset of these transcripts as specifically sleep-enhanced or sleep-repressed by requiring that their expression also change over the course of unperturbed sleep. 3% and 6% of the assayed transcripts showed sleep specific changes in the lung and heart respectively. Sleep specific transcripts in these tissues demonstrated highly significant overlap and shared temporal dynamics. Markers of cellular stress and the unfolded protein response were reduced during sleep in both tissues. These results mirror previous findings in brain. Sleep-enhanced pathways reflected the unique metabolic functions of each tissue. Transcripts related to carbohydrate and sulfur metabolic processes were enhanced by sleep in the lung, and collectively favor buffering from oxidative stress. DNA repair and protein metabolism annotations were significantly enriched among the sleep-enhanced transcripts in the heart. Our results also suggest that sleep may provide a Zeitgeber, or synchronizing cue, in the lung as a large cluster of transcripts demonstrated systematic changes in inter-animal variability as a function of both sleep duration and circadian time.Conclusion: Our data support the notion that the molecular consequences of sleep/wake behavioral state extend beyond the brain to include peripheral tissues. Sleep state induces a highly overlapping response in both heart and lung. We conclude that sleep enhances organ specific molecular functions and that it has a ubiquitous role in reducing cellular metabolic stress in both brain and peripheral tissues. Finally, our data suggest a novel role for sleep in synchronizing transcription in peripheral tissues.