Background Cellular 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 fulfill specific energy demands across the tissues. To the yet, this tissue-specific 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 & methods The 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 tissue-specific diversity based on the quantification of mitochondrial DNA copy numbers was performed and also comprised an expression study of 13 protein genes encoded by mitochondrial genome. Results The investigated tissues showed striking differences in OXPHOS activities and CS-specific activities. The functional activity of individual OXPHOS complex I was significantly higher in the liver compared to muscle and brain. Tissue-dependent differences again reflected on OXPHOS complex III and V activities, with the liver showing significantly the highest specific activities compared to the heart, ovary, and brain. Additionally, there are considerable differences in the CS-specific activity between tissues, with the ovary, kidney, and liver having significantly greater values. Furthermore, we observed the mtDNA copy number was strictly tissue-specific, indicating the distinct bioenergetics and metabolic requirements of various tissues, with muscle and brain tissues exhibiting the highest levels. Moreover, the CS-specific activity also differs markedly between tissues, with significantly higher values for the ovary, kidney, and liver. Further, we observed a strict tissue specificity of mtDNA copy number, reflecting the specific 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. Conclusion Overall, our results indicate the existence of a tissue-specific variation in mitochondrial activity, bioenergetics, and protein gene expression of mitochondria among various types of buffalo tissues. This study serves as a critical first 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.

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.

Pregnancy is a highly energy-demanding process that utilizes the ATP from mitochondria and balances adequate functions and nutritional requirements. Many of these functions are driven by the placenta, which provides appropriate requirements for maintaining the pregnancy and development of fetal growth. As calving-related and postpartum disorders in mothers and offspring are connected to poor pregnancy circumstances, placental function is also critical for long-term health. During gestation, the placental cellular structure undergoes cell differentiation, leading to various modifications like variations in morphology, bioenergetics, hormones, nutrition, and metabolic and mitochondrial changes in the placenta and also increased metabolic activity, free radical production, and oxidative damage. Any changes to this process could manifest in an excess production of reactive oxygen species, which could contribute to the retention of placenta. Retention of the placenta is the most common calving-related postpartum reproductive disorder in highly productive animals, which negatively influences the productive and reproductive performance of the animals. It occurs due to an imbalance in various factors such as disorders; hormonal and nutritional disturbance, metabolic changes, hereditary predispositions, antioxidants, and negative energy balance collaborate in the progression of oxidative stress and may be mitochondrial dysfunction. Mitochondria are energy providers to the placenta for various functions and the leading site for steroidogenesis, which is one of the essential factors for the retention of the placenta. An increase in placental oxidative stress and various factors linked with placental mitochondria are associated with various placental disorders. Thus, here we review the relationship between the mechanism underlying placental mitochondrial dysfunction and fetal membrane expulsion. Mitochondrial dysfunctions may be a substantial causative factor in the retention of the placenta same, as various reproductive disorders. We outline the placental mitochondrial functions and their relationship with causative factors of retained placenta in bovine.

Background Buffaloes' energy status is a vital attribute influencing their phenotypic traits and overall health. Mitochondria, primarily through oxidative phosphorylation (OXPHOS), contribute significantly to energy generation; both nuclear (nDNA) and mitochondrial (mtDNA) genomes are involved in OXPHOS process. Previous studies from our laboratory have reported tissue heterogeneity in buffaloes, particularly in mitochondrial functional attributes, is influenced by the mtDNA. Furthermore, there is evidence of higher OXPHOS complex I activity and expression of OXPHOS complex I genes encoded by the mtDNA in various buffalo tissues. Complex I is the largest and mostly involved in energy generation and maintenance of reactive oxygen species. This largest OXPHOS complex consists of proteins encoded by both nDNA and mtDNA. Currently, the tissue-specific expression of nDNA encoded OXPHOS complex I genes expression in metabolically active tissues of buffalo are not well understood. Therefore, the study aimed to investigate the tissue-specific expression of nDNA-encoded OXPHOS complex I genes in buffaloes. Methods and Results To analyze the expression of the OXPHOS complex I genes encoded by nDNA across the various tissues to gain insight into tissue-specific diversity in energy metabolism, RNA-Seq was performed on total RNA extracted from kidney, heart, brain, and ovary of four buffaloes, subsequently identified differentially expressed genes (DEGs) in various tissues comparison. Out of 57 identified OXPHOS complex I genes encoded by nDNA, 51 genes were found to be expressed in each tissue. Comparative analysis revealed 12 DEGs between kidney and brain, 30 for kidney vs ovary, 26 for kidney vs heart, 20 for heart vs brain, 38 for heart vs ovary, and 26 for brain vs ovary, with log2(FC)≥1 and p<0.05. Notably, compared to the ovary, other tissues such as the heart, kidney cortex, and brain exhibited a higher proportion of up-regulated OXPHOS complex I genes. The finding of nuclear derived OXPHOS complex I genes expression of our study showed a close relation with our earlier published report from our laboratory concerning OXPHOS complex I activity. Conclusions Our findings revealed substantial changes in OXPHOS complex I subunit gene expression encoded by nDNA across tissues, with up-regulation of specific genes potentially reflecting increased metabolic needs or adaptation to specific roles. These tissue-specific differential expression patterns of OXPHOS complex I subunit-related genes provide valuable insights into the importance of their integrity for tissue-specific energy requirements, mitochondrial function, and their implications for buffalo's productive and reproductive health.