Transcriptome Analysis of Goat Mammary Gland Tissue Reveals the Adaptive Strategies and Molecular Mechanisms of Lactation and Involution

MiR-2284b regulation of α-s1 casein synthesis in mammary epithelial cells of dairy goats

The lactation character of dairy goats is the most important characteristic, and milk protein is an important index to evaluate milk quality. Casein accounts for more than 80% of the total milk protein in goat milk and is the main component of milk protein. Using GMECs (goat mammary epithelial cells) as the research object, the CHECK2 vector of the CSN1S1 gene and the overexpression vector of pcDNA 3.1 were constructed, and the mimics of miR-2284b and the interfering RNA of CSN1S1 were synthesized. Using PCR, RT-qPCR, a dual luciferase activity detection system, EdU, CCK8, cell apoptosis detection and ELISA detection, we explored the regulatory mechanism and molecular mechanism of miR-2284b regulation of αs1-casein synthesis in GMECs. miR-2284b negatively regulates proliferation and apoptosis of GMECs and αs1-casein synthesis. Two new gene sequences of CSN1S1 were discovered. CSN1S1-1/-2 promoted the proliferation of GMECs and inhibited cell apoptosis. However, it had no effect on αs1-casein synthesis. MiR-2284b negatively regulates αs1-casein synthesis in GMECs by inhibiting the CSN1S1 gene. These results all indicated that miR-2284b could regulate αs1-casein synthesis, thus playing a theoretical guiding role in the future breeding process of dairy goats and accelerating the development of dairy goat breeding.

Protein Dynamic Landscape during Mouse Mammary Gland Development from Virgin to Pregnant, Lactating, and Involuting Stages

The mammary gland undergoes significant physiological changes as it undergoes a transition from virgin to pregnancy, lactation, and involution. However, the dynamic role of proteins in regulating these processes during mouse mammary gland development has not been thoroughly explored. In this study, we collected mouse mammary gland tissues from mature virgins aged 8-10 weeks (V), day 16 of pregnancy (P16d), day 12 of lactation (L12d), day 1 of forced weaning (FW 1d), and day 3 of forced weaning (FW 3d) stages for analysis using DIA-based quantitative proteomics technology. A total of 3,312 proteins were identified, of which 843 were DAPs that were categorized into nine clusters based on their abundance changes across developmental stages. Notably, DAPs in cluster 2, which peaked at the L12d stage, were primarily associated with mammary gland development and lactation. The protein-protein interaction network revealed that the epidermal growth factor (EGF) was central to this cluster. Our study provides a comprehensive overview of the mouse mammary gland development proteome and identifies some important proteins, such as EGF, Janus kinase 1 (JAK1), and signal transducer and activator of transcription 6 (STAT6) that may serve as potential targets for future research to provide guidelines for a deeper understanding of the developmental biology of mammary glands.

Comparative transcriptome analysis of E. coli & Staphylococcus aureus infected goat mammary epithelial cells reveals genes associated with infection

Mastitis, an inflammatory disease of the mammary gland, imposes a significant financial burden on the dairy sector. However, the specific molecular mechanisms underlying their interactions with goat mammary epithelial cells (GMECs) remain poorly understood. This study aimed to investigate the transcriptomic response of GMECs during infection with E. coli and S. aureus, providing insights into the host-pathogen interactions. Differential expression of gene (DEGs) analysis was done to find genes and pathways dysregulated in the wake of infection. E. coli infection triggered a robust upregulation of immune response genes, including pro-inflammatory chemokines and cytokines as well as genes involved in tissue repair and remodeling. Conversely, S. aureus infection showed a more complex pattern, involving the activation of immune-related gene as well as those involved in autophagy, apoptosis and tissue remodeling. Furthermore, several key pathways, such as Toll-like receptor signaling and cytokine-cytokine receptor interaction, were differentially modulated in response to each pathogen. Understanding the specific responses of GMECs to these pathogens will provide a foundation for understanding the complex dynamics of infection and host response, offering potential avenues for the development of novel strategies to prevent and treat bacterial infections in both animals and humans.

Fluoxetine treatment during the postpartal period may have short-term impacts on murine maternal skeletal physiology

Postpartum depression affects many individuals after parturition, and selective serotonin reuptake inhibitors (SSRIs) are often used as the first-line treatment; however, both SSRIs and lactation are independently associated with bone loss due to the role of serotonin in bone remodeling. Previously, we have established that administration of the SSRI fluoxetine during the peripartal period results in alterations in long-term skeletal characteristics. In the present study, we treated mice with either a low or high dose of fluoxetine during lactation to determine the consequences of the perturbation of serotonin signaling during this time period on the dam skeleton. We found that lactational fluoxetine exposure affected both cortical and trabecular parameters, altered gene expression and circulating markers of bone turnover, and affected mammary gland characteristics, and that these effects were more pronounced in the dams that were exposed to the low dose of fluoxetine in comparison to the high dose. Fluoxetine treatment during the postpartum period in rodents had short term effects on bone that were largely resolved 3 months post-weaning. Despite the overall lack of long-term insult to bone, the alterations in serotonin-driven lactational bone remodeling raises the question of whether fluoxetine is a safe option for the treatment of postpartum depression.

Identification of milk-related genes and regulatory networks in Bactrian camel either supplemented or under grazing

Using gene co-expression networks to understand dynamic characterizations in lactating animals becomes a common method. However, there are rarely reporters focusing on milk traits in Bactrian camel by high-throughput sequencing. We used RNA-seq to generate the camel transcriptome from the blood of 16 lactating Alxa Bactrian camel in different feeding groups. In total, we obtained 1185 milk-related genes correlated with milk yield, milk protein, milk fat, and milk lactose across the WGCNA analysis. Moreover, 364 milk-related genes were differentially expressed between supplementation and grazing feeding groups. The differential expression-camel milk-related genes CMRGs (DE-CMRGs) in supplement direct an intensive gene co-expression network to improve milk performance in lactating camels. This study provides a non-invasive method to identify the camel milk-related genes in camel blood for four primary milk traits and valuable theoretical basis and research ideas for the study of the milk performance regulation mechanism of camelid animals.