Tissue heterogeneity of mitochondrial activity, biogenesis and mitochondrial protein gene expression in buffalo

Abstract

BackgroundCellular metabolism is most invariant processes, occurring in all living organisms which involve mitochondrial proteins from both nuclear and mitochondrial genome. Mitochondrial genome and gene expression has played a central role in the oxidative phosphorylation system biogenesis and metabolism of energy. The mitochondrial DNA (mtDNA) copy number, its protein genes expression and activity in tissues vary between various tissues to ful ll speci c energy demands across the tissues. To the yet, this tissue-speci c diversity is unaware in terms of mitochondrial biogenesis and protein-coding gene expression in the metabolically active tissue of buffalo. Thus, we assessed the variations in mitochondrial functional assay, mtDNA cellular number, and protein gene expression by investigating six bovine tissues. Materials & methodsThe liver, kidney, heart, muscle, ovary and brain of the same freshly slaughtered buffaloes (n = 3) were investigated for their differences in mitochondrial bioenergetics by measuring the individual OXPHOS complexes and enzymatic activity of citrate synthase in isolated mitochondria. The evaluation of tissuespeci c diversity based on the quanti cation of mitochondrial DNA copy numbers was performed and also comprised an expression study of 13 protein genes encoded by mitochondrial genome. ResultsThe investigated tissues showed striking differences in OXPHOS activities and CS-speci c activities. The functional activity of individual OXPHOS complex I was signi cantly higher in the liver compared to muscle and brain. Tissue-dependent differences again re ected on OXPHOS complex III and V activities, with the liver showing signi cantly the highest speci c activities compared to the heart, ovary, and brain.Additionally, there are considerable differences in the CS-speci c activity between tissues, with the ovary, kidney, and liver having signi cantly greater values. Furthermore, we observed the mtDNA copy number was strictly tissue-speci c, indicating the distinct bioenergetics and metabolic requirements of various tissues, with muscle and brain tissues exhibiting the highest levels. Moreover, the CS-speci c activity also differs markedly between tissues, with signi cantly higher values for the ovary, kidney, and liver. Further, we observed a strict tissue speci city of mtDNA copy number, re ecting the speci c energy and metabolic demands of different tissues, with brain and muscle tissues showing the highest values. Among 13 PCGs expression analyses, mRNA abundances in all genes were differentially expressed among the different tissue. ConclusionPage 3/22 Overall, our results indicate the existence of a tissue-speci c variation in mitochondrial activity, bioenergetics, and protein gene expression of mitochondria among various types of buffalo tissues. This study serves as a critical rst stage in gathering vital comparable data about the physiological function of mitochondria in energy metabolism in distinct tissues, laying the groundwork for future mitochondrial based diagnosis and research.

Deciphering Tissue-Specific Expression Profiles of Mitochondrial Genome-encoded tRNAs and rRNAs through Transcriptomic Profiling in Buffalo

“…Previous investigations conducted in our laboratory elucidated the varied functionality exhibited by discrete OXPHOS complexes and the disparate expression patterns of mitochondrial and nuclearencoded protein genes integral to OXPHOS across diverse tissues (Sadeesh et al, 2023a;Sadeesh et al, 2023b). Nonetheless, the examination of tissue-speci c gene expression pertaining to mitochondrialencoded non-coding RNAs has hitherto remained unexplored.…”

“…Additionally, mitochondria import over 1000 different proteins, with only a subset directly involved in translation processes (Sche er et al, 2001;Sissler et al, 2017). Mammalian tissues, re ecting diverse energy demands, exhibit signi cant variations in metabolic pro les, which can dynamically change throughout development in response to physiological adaptations and under pathological conditions (Alston et al, 2017;Sadeesh et al, 2023a). Furthermore, the quality of meat is also in uenced by mitochondrial functionality and the distinct proteome pro les of mitochondria (Ramanathan et al, 2021;Zhai et al, 2022).…”

Neuronal Ceroid Lipofuscinosis in a Mixed-Breed Dog with a Splice Site Variant in CLN6

“…However, there were tissue-specific differences in the ultrastructure of the storage body contents. This may reflect differences in the molecular composition of the storage body precursors in different tissues, including tissue-specific differences in mitochondrial molecular composition [ 15 , 16 , 17 ]. Like other NCLs and similar neurodegenerative disorders, the proband exhibited significant neuroinflammation.…”