Bhlhe40 differentially regulates the function and number of peroxisomes and mitochondria in myogenic cells

Autor: Chien Han Kao, Yi An Juan, Shih Ying Chung, Lulus Putri Aninda, Hsuan Chia Chang, Yi Huan Chen, Shen Liang Chen, Wei Cheng Chen
Rok vydání: 2019
Předmět:
0301 basic medicine
Clinical Biochemistry
Skeletal muscle
PGC-1α
Gene Expression
Oxidative phosphorylation
Peroxisome
Mitochondrion
Muscle Development
Biochemistry
Myoblasts
Mice
03 medical and health sciences
Oxygen Consumption
0302 clinical medicine
Gene expression
Basic Helix-Loop-Helix Transcription Factors
Peroxisomes
Animals
Humans
RNA
Small Interfering
lcsh:QH301-705.5
Transcription factor
Bhlhe40
Unsaturated fatty acid
Homeodomain Proteins
lcsh:R5-920
Gene knockdown
Chemistry
Fatty Acids
Organic Chemistry
Catalase
Immunohistochemistry
Mitochondria
Rats
Cell biology
Glucose
030104 developmental biology
lcsh:Biology (General)
Gene Knockdown Techniques
Oxidative metabolism
lcsh:Medicine (General)
Reactive Oxygen Species
Oxidation-Reduction
Biomarkers
030217 neurology & neurosurgery
Biogenesis
Research Paper
Zdroj: Redox Biology
Redox Biology, Vol 20, Iss, Pp 321-333 (2019)
ISSN: 2213-2317
DOI: 10.1016/j.redox.2018.10.009
Popis: PGC-1α is a key regulator of oxidative metabolism facilitating the expression of genes critical for the function and biogenesis of the two key oxidative organelles, mitochondria and peroxisomes, in skeletal muscle (SKM) and other organs. Our recent studies have found that the transcription factor Bhlhe40 negatively regulates PGC-1α gene expression and its coactivational activity, therefore, this factor should have profound influence on the biogenesis and metabolic activity of mitochondria and peroxisomes. Here we found that both the number and activity of peroxisomes were increased upon knockdown of Bhlhe40 expression but were repressed by its over-expression. Mitochondrial number and efficiency were significantly reduced by Bhlhe40 knockdown, resulting in the burst of ROS. Over-expression of a constitutively active PGC-1α-interactive domain (named as VBH135) of Bhlhe40 mimicked the effects of its knockdown on peroxisomes but simultaneously reduced ROS level. Furthermore, the efficiency, but not the number, of mitochondria was also increased by VBH135, suggesting differential regulation of peroxisomes and mitochondria by Bhlhe40. Unsaturated fatty acid oxidation, insulin response, and oxidative respiration were highly enhanced in Bhlhe40 knockdown or VBH135 over-expressed cells, suggesting the importance of Bhlhe40 in the regulation of unsaturated fatty acid and glucose oxidative metabolism. Expression profiling of genes important for either organelle also supports differential regulation of peroxisomes and mitochondria by Bhlhe40. These observations have established the important role of Bhlhe40 in SKM oxidative metabolism as the critical regulator of peroxisome and mitochondrion biogenesis and functions, and thus should provide a novel route for developing drugs targeting SKM metabolic diseases.
Graphical abstract Bhlhe40 normally represses PGC-1α expression and its coactivational activity on target gene promoters. When Bhlhe40 is knockdown (as in C2C12-ShBhlhe40 cells), PGC-1α and its target genes, such as SOD2 and peroxisome related genes (Pex), is increased to enhance/increase peroxisome function and number. Mitochondria (MITO) related genes are regulated differentially, which leads to reduced MITO efficiency (in grey) and surged ROS level. In C2C12-VBH135 cells, wildtype Bhlhe40 is competed off the promoters and the expression of both Pex and HO1 genes are increased, which increased peroxisome function and number. Although MITO genes are also regulated differentially, VBH135 increased MITO efficiency (in red) and reduced ROS level.fx1
Highlights • Knockout of Bhlhe40 increased ROS but over-expression of Bhlhe40 reduced ROS. • Peroxisome number was increased by Bhlhe40 knockout or VBH135 overexpression. • Mitochondrial efficiency was reduced by Bhlhe40 knockout but increased by VBH135. • Oxidative respiration was enhanced by Bhlhe40 knockdown or VBH135 overexpression. • Bhlhe40 repressed PGC-1α coactivation of nuclear gene expression.
Databáze: OpenAIRE
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