TMT based deep proteome analysis of buffalo mammary epithelial cells and identification of novel protein signatures during lactogenic differentiation

TTLL12 has a potential oncogenic activity, suppression of ligation of nitrotyrosine to the C-terminus of detyrosinated α-tubulin, that can be overcome by molecules identified by screening a compound library

Tubulin tyrosine ligase 12 (TTLL12) is a promising target for therapeutic intervention since it has been implicated in tumour progression, the innate immune response to viral infection, ciliogenesis and abnormal cell division. It is the most mysterious of a fourteen-member TTL/TTLL family, since, although it is the topmost conserved in evolution, it does not have predicted enzymatic activities. TTLL12 seems to act as a pseudo-enzyme that modulates various processes indirectly. Given the need to target its functions, we initially set out to identify a property of TTLL12 that could be used to develop a reliable high-throughput screening assay. We discovered that TTLL12 suppresses the cell toxicity of nitrotyrosine (3-nitrotyrosine) and its ligation to the C-terminus of detyrosinated α-tubulin (abbreviated to ligated-nitrotyrosine). Nitrotyrosine is produced by oxidative stress and is associated with cancer progression. Ligation of nitrotyrosine has been postulated to be a check-point induced by excessive cell stress. We found that the cytotoxicities of nitrotyrosine and tubulin poisons are independent of one another, suggesting that drugs that increase nitrotyrosination could be complementary to current tubulin-directed therapeutics. TTLL12 suppression of nitrotyrosination of α-tubulin was used to develop a robust cell-based ELISA assay that detects increased nitrotyrosination in cells that overexpress TTLL12 We adapted it to a high throughput format and used it to screen a 10,000 molecule World Biological Diversity SETTM collection of low-molecular weight molecules. Two molecules were identified that robustly activate nitrotyrosine ligation at 1 μM concentration. This is the pioneer screen for molecules that modulate nitrotyrosination of α-tubulin. The molecules from the screen will be useful for the study of TTLL12, as well as leads for the development of drugs to treat cancer and other pathologies that involve nitrotyrosination.

Molecular complexity of mammary glands development: a review of lactogenic differentiation in epithelial cells

The mammary gland is a dynamic organ with various physiological processes like cellular proliferation, differentiation, and apoptosis during the pregnancy-lactation-involution cycle. It is essential to understand the molecular changes during the lactogenic differentiation of mammary epithelial cells (MECs, the milk-synthesizing cells). The MECs are organized as luminal milk-secreting cells and basal myoepithelial cells (responsible for milk ejection by contraction) that form the alveoli. The branching morphogenesis and lactogenic differentiation of the MECs prepare the gland for lactation. This process is governed by many molecular mediators including hormones, growth factors, cytokines, miRNAs, regulatory proteins, etc. Interestingly, various signalling pathways guide lactation and understanding these molecular transitions from pregnancy to lactation will help researchers design further research. Manipulation of genes responsible for milk synthesis and secretion will promote augmentation of milk yield in dairy animals. Identifying protein signatures of lactation will help develop strategies for persistent lactation and shortening the dry period in farm animals. The present review article discusses in details the physiological and molecular changes occurring during lactogenic differentiation of MECs and the associated hormones, regulatory proteins, miRNAs, and signalling pathways. An in-depth knowledge of the molecular events will aid in developing engineered cellular models for studies related to mammary gland diseases of humans and animals.

CRISPR-Cas9 based knockout of S100A8 in mammary epithelial cells enhances cell proliferation and triggers oncogenic transformation via the PI3K-Akt pathway: Insights from a deep proteomic analysis

S100A8 is a calcium-binding protein with multiple functions, including being a chemoattractant for phagocytes and playing a key role in the inflammatory response. Its expression has been shown to influence epithelial-mesenchymal transition (EMT) and metastasis in colorectal cancer. However, the role of S100A8 in cell proliferation and differentiation remains unknown. In this study, we used the CRISPR-Cas9 system to knock out S100A8 in healthy mammary epithelial cells and investigated the resulting changes in proteome profiling and signaling pathways. Our results showed that S100A8 knockout led to an increase in cell proliferation and migration, reduced cell-cell adhesion, and increased apoptosis compared to wildtype cells. Proteomics data indicated that S100A8 significantly affects cell cycle progression, cell proliferation, and cell survival through the PI3K-Akt pathway. Furthermore, our findings suggest that S100A8 function is associated with Pten expression, a negative regulator of the PI3K-Akt pathway. These results indicate that S100A8 dysregulation in healthy cells can lead to altered cellular physiology and higher proliferation, similar to cancerous growth. Therefore, maintaining S100A8 expression is critical for preserving healthy cell physiology. This study provides novel insights into the role of S100A8 in cell proliferation and differentiation and its potential relevance to cancer biology. SIGNIFICANCE: The study suggests that maintaining S100A8 expression is critical for preserving healthy cell physiology, and dysregulation of S100A8 in healthy cells can lead to altered cellular physiology and higher proliferation, similar to cancerous growth. Therefore, targeting the PI3K-Akt pathway or regulating Pten expression, a negative regulator of the PI3K-Akt pathway, may be potential strategies for cancer treatment by controlling S100A8 dysregulation. Additionally, S100A8 and S100A9 have been shown to promote metastasis of breast carcinoma by forming a metastatic milieu. However, the differential expression of S100A8 in tumors and its dual effects of antitumor and protumor make the relationship between S100A8 and tumors complicated. Currently, most research focuses on the function of S100A8 as a secretory protein in the microenvironment of tumors, and its function inside healthy cells without forming dimers remains unclear. Furthermore, the study provides insight into the role of S100A8 in cell proliferation and differentiation, which may have implications for other diseases beyond cancer. The functional role of S100A8 in normal mammary epithelial cells remains completely uncertain. Therefore, the objective of this study is to investigate the function of S100A8 on proliferation in mammary epithelial cells after its deletion and to elucidate the underlying proteins involved in downstream signaling. Our findings indicate that the deletion of S100A8 leads to excessive proliferation in normal mammary epithelial cells, reduces apoptosis, and affects cell-cell adhesion molecules required for cellular communication, resulting in a cancer-like phenotype.

Dynamic Profile of the Yak Mammary Transcriptome during the Lactation Cycle

The objective of this study was to assess the transcriptome of the mammary tissue of four yaks during the whole lactation cycle. For this purpose, biopsies of the mammary gland were performed at -30, -15, 1, 15, 30, 60, 120, 180, and 240 days relative to parturition (d). The transcriptome analysis was performed using a commercial bovine microarray platform and the results were analyzed using several bioinformatic tools. The statistical analysis using an overall false discovery rate ≤ 0.05 for the effect of whole lactation and p < 0.05 for each comparison identified >6000 differentially expressed genes (DEGs) throughout lactation, with a large number of DEGs observed at the onset (1 d vs. -15 d) and at the end of lactation (240 d vs. 180 d). Bioinformatics analysis revealed a major role of genes associated with BTA3, BTA4, BTA6, BTA9, BTA14, and BTA28 in lactation. Functional analysis of DEG underlined an overall induction of lipid metabolism, suggesting an increase in triglycerides synthesis, likely regulated by PPAR signaling. The same analysis revealed an induction of amino acid metabolism and secretion of protein, with a concomitant decrease in proteasome, indicating a major role of amino acid handling and reduced protein degradation in the synthesis and secretion of milk proteins. Glycan biosynthesis was induced for both N-glycan and O-glycan, suggesting increased glycan content in the milk. The cell cycle and immune response, especially antigen processing and presentation, were strongly inhibited during lactation, suggesting that morphological changes are minimized during lactation, while the mammary gland prevents immune hyper-response. Transcripts associated with response to radiation and low oxygen were enriched in the down-regulated DEG affected by the stage of lactation. Except for this last finding, the functions affected by the transcriptomic adaptation to lactation in mammary tissue of yak are very similar to those observed in dairy cows.

Critical Review on Physiological and Molecular Features during Bovine Mammary Gland Development: Recent Advances

The mammary gland is a unique organ with the ability to undergo repeated cyclic changes throughout the life of mammals. Among domesticated livestock species, ruminants (cattle and buffalo) constitute a distinct class of livestock species that are known milk producers. Cattle and buffalo contribute to 51 and 13% of the total milk supply in the world, respectively. They also play an essential role in the development of the economy for farming communities by providing milk, meat, and draft power. The development of the ruminant mammary gland is highly dynamic and multiphase in nature. There are six developmental stages: embryonic, prepubertal, pubertal, pregnancy, lactation, and involution. There has been substantial advancement in our understanding of the development of the mammary gland in both mouse and human models. Until now, there has not been a thorough investigation into the molecular processes that underlie the various stages of cow udder development. The current review sheds light on the morphological and molecular changes that occur during various developmental phases in diverse species, with a particular focus on the cow udder. It aims to explain the physiological differences between cattle and non-ruminant mammalian species such as humans, mice, and monkeys. Understanding the developmental biology of the mammary gland in molecular detail, as well as species-specific variations, will facilitate the researchers working in this area in further studies on cellular proliferation, differentiation, apoptosis, organogenesis, and carcinogenesis. Additionally, in-depth knowledge of the mammary gland will promote its use as a model organ for research work and promote enhanced milk yield in livestock animals without affecting their health and welfare.

Impact of CRISPR-Cas9-Based Genome Engineering in Farm Animals

Humans are sorely over-dependent on livestock for their daily basic need of food in the form of meat, milk, and eggs. Therefore, genetic engineering and transgenesis provide the opportunity for more significant gains and production in a short span of time. One of the best strategies is the genetic alteration of livestock to enhance the efficiency of food production (e.g., meat and milk), animal health, and welfare (animal population and disease). Moreover, genome engineering in the bovine is majorly focused on subjects such as disease resistance (e.g., tuberculosis), eradicate allergens (e.g., beta-lactoglobulin knock-out), products generation (e.g., meat from male and milk from female), male or female birth specifically (animal sexing), the introduction of valuable traits (e.g., stress tolerance and disease resistance) and their wellbeing (e.g., hornlessness). This review addressed the impressive genome engineering method CRISPR, its fundamental principle for generating highly efficient target-specific guide RNA, and the accompanying web-based tools. However, we have covered the remarkable roadmap of the CRISPR method from its conception to its use in cattle. Additionally, we have updated the comprehensive information on CRISPR-based gene editing in cattle.