AMP-activated protein kinase mediates activity-dependent regulation of peroxisome proliferator-activated receptor γ coactivator-1α and nuclear respiratory factor 1 expression in rat visual cortical neurons

Neuroscience ◽  
2010 ◽  
Vol 169 (1) ◽  
pp. 23-38 ◽  
Author(s):  
L. Yu ◽  
S.J. Yang
2010 ◽  
Vol 47 ◽  
pp. 69-84 ◽  
Author(s):  
François R. Jornayvaz ◽  
Gerald I. Shulman

Although it is well established that physical activity increases mitochondrial content in muscle, the molecular mechanisms underlying this process have only recently been elucidated. Mitochondrial dysfunction is an important component of different diseases associated with aging, such as Type 2 diabetes and Alzheimer’s disease. PGC-1α (peroxisome-proliferator-activated receptor γ co-activator-1α) is a co-transcriptional regulation factor that induces mitochondrial biogenesis by activating different transcription factors, including nuclear respiratory factor 1 and nuclear respiratory factor 2, which activate mitochondrial transcription factor A. The latter drives transcription and replication of mitochondrial DNA. PGC-1α itself is regulated by several different key factors involved in mitochondrial biogenesis, which will be reviewed in this chapter. Of those, AMPK (AMP-activated protein kinase) is of major importance. AMPK acts as an energy sensor of the cell and works as a key regulator of mitochondrial biogenesis. AMPK activity has been shown to decrease with age, which may contribute to decreased mitochondrial biogenesis and function with aging. Given the potentially important role of mitochondrial dysfunction in the pathogenesis of numerous diseases and in the process of aging, understanding the molecular mechanisms regulating mitochondrial biogenesis and function may provide potentially important novel therapeutic targets.


2021 ◽  
Author(s):  
Nan Niu ◽  
Hui Li ◽  
Xiancai Du ◽  
Chan Wang ◽  
Junliang Li ◽  
...  

Abstract Background: Hypoxia is a primary inducer of cardiomyocyte injury, its significant marker being hypoxia-induced cardiomyocyte apoptosis. Nuclear respiratory factor-1 (NRF-1) and hypoxia-inducible factor-1α (HIF-1α) are transcriptional regulatory elements implicated in multiple biological functions, including oxidative stress response. However, their roles in hypoxia-induced cardiomyocyte apoptosis remain unknown. The effect HIF-α, together with NRF-1, exerts on cardiomyocyte apoptosis also remains unclear. Methods: We established a myocardial hypoxia model and investigated the effects of these proteins on the proliferation and apoptosis of rat cardiomyocytes (H9C2) under hypoxia. Further, we examined the association between NRF-1 and HIF-1α to improve the current understanding of NRF-1 anti-apoptotic mechanisms. Results: The results show that NRF-1 and HIF-1α are important anti-apoptotic molecules in H9C2 cells under hypoxia, although their regulatory mechanisms differ. NRF-1 could bind to the promoter region of Hif1a and negatively regulate its expression. Additionally, HIF-1β exhibited competitive binding with NRF-1 and HIF-1α, demonstrating a synergism between NRF-1 and the peroxisome proliferator-activated receptor-gamma coactivator-1α. Conclusion: These results indicate that cardiomyocytes can regulate different molecular patterns to tolerate hypoxia, providing a novel methodological framework for studying cardiomyocyte apoptosis under hypoxia.


2021 ◽  
Author(s):  
Nan Niu ◽  
Hui Li ◽  
Xiancai Du ◽  
Chan Wang ◽  
Junliang Li ◽  
...  

Abstract Hypoxia is a primary inducer of cardiomyocyte injury, its significant marker being hypoxia-induced cardiomyocyte apoptosis. Nuclear respiratory factor-1 (NRF-1) and hypoxia-inducible factor (HIF)-1α are transcriptional regulatory elements implicated in multiple biological functions, including oxidative stress response. However, their roles in hypoxia-induced cardiomyocyte apoptosis remain unknown. The effect HIF-α, together with NRF-1, exerts on cardiomyocyte apoptosis also remains unclear. We established a myocardial hypoxia model and investigated the effects of these proteins on the proliferation and apoptosis of rat cardiomyocytes (H9C2) under hypoxia. Further, we examined the association between NRF-1 and HIF-1α to improve the current understanding of NRF-1 anti-apoptotic mechanisms. The results showed that NRF-1 and HIF-1α are important anti-apoptotic molecules in H9C2 cells under hypoxia, although their regulatory mechanisms differ. NRF-1 could bind to the promoter region of Hif-1α and negatively regulate its expression. Additionally, HIF-1β exhibited competitive binding with NRF-1 and HIF-1α, demonstrating a synergism between NRF-1 and the peroxisome proliferator-activated receptor-gamma coactivator-1α. These results indicate that cardiomyocytes can regulate different molecular patterns to tolerate hypoxia, providing a novel methodological framework for studying cardiomyocyte apoptosis under hypoxia.


2015 ◽  
Vol 34 (3) ◽  
pp. 274-283 ◽  
Author(s):  
Farshad Arsalandeh ◽  
Shahin Ahmadian ◽  
Forough Foolad ◽  
Fariba Khodagholi ◽  
Mahdi M. Farimani ◽  
...  

In the present study, the neuroprotective effect of 5-hydroxy-6,7,4′-trimethoxyflavone (flavone 1), a natural flavone, was investigated in comparison with another flavone, 5,7,4′-trihydroxyflavone (flavone 2) on the hippocampus of amyloid beta (Aβ)-injected rats. Rats were treated with the 2 flavones (1 mg/kg/d) for 1 week before Aβ injection. Seven days after Aβ administration, memory function of rats was assessed in a passive avoidance test (PAT). Changes in the levels of mitochondrial transcription factor A (TFAM), peroxisome proliferator-activated receptor γ coactivator 1 α (PGC-1α), phospho-adenosine monophosphate (AMP)-activated protein kinase (pAMPK), AMPK, phospho-cAMP-responsive element-binding protein (CREB), CREB, and nuclear respiratory factor 1 (NRF-1) proteins were determined by Western blot analysis. Our results showed an improvement in memory in rats pretreated with flavonoids. At the molecular level, phosphorylation of CREB, known as the master modulator of memory processes, increased. On the other hand, the level of mitochondrial biogenesis factors, PGC-1α and its downstream molecules NRF-1 and TFAM significantly increased by dietary administration of 2 flavones. In addition, flavone 1 and flavone 2 prevented mitochondrial swelling and mitochondrial membrane potential reduction. Our results provided evidence that flavone 1 is more effective than flavone 2 presumably due to its O-methylated groups. In conclusion, it seems that in addition to classical antioxidant effect, flavones exert part of their protective effects through mitochondrial biogenesis.


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