Fig. 4: Knockdown of Sirt5 impairs mitochondrial homeostasis and leads to a decrease in ETC complex subunits in NP cells.

a Representative TEM images of mitochondria in NP cells from the si-NC and si-Sirt5 groups (n = 3). Yellow arrow: normal mitochondria. Red arrow: unhealthy mitochondria. Black scale bar = 2 μm; white scale bar = 1 μm. b Representative immunohistochemical staining of the structure of mitochondria in NP cells from the si-NC and si-Sirt5 groups (n = 3). White scale bar = 50 μm; green scale bar = 10 μm. c Seahorse analysis of the oxygen consumption rate (OCR) in the si-NC and si-Sirt5 NP cells. The OCR was measured continuously throughout the experimental period at baseline and in the presence of the indicated drugs: 1 μM oligomycin, 2 μM FCCP, and 1 μM rotenone with 1 μM antimycin A (R + A). d Quantification of maximal respiration, ATP production, and basal respiration of the data from mitochondrial stress tests (n = 3). e Quantification of ATP levels in NP cells from the si-NC and si-Sirt5 groups (n = 6). f, g Western blotting analysis and quantification of ATP5F1A, UQCRC2, SDHB, NDUFB8, and COX IV protein expression (normalized to β-actin expression, n = 3). Differences between two groups were analyzed by Student’s t test. The data in the figures represent the mean ± S.D. The P value is shown, *P < 0.05, **P < 0.01.