Can widely used cell type markers predict the suitability of immortalized or primary mammary epithelial cell models?

Cellular characteristics and milk component productivity of primary bovine mammary cells for cell-cultured milk component production

Despite the increasing demand for milk, there is a simultaneous growth in awareness regarding sustainable dairy farming and concerns about environmental issues. The concept of generating milk components without traditional dairy farming has been introduced through the utilization of bovine mammary cells. However, the establishment of a robust primary bovine mammary alveolar cells for cell-cultured milk component production remains a challenge. Hence, the aim of this study was to assess the cellular attributes and milk component productivity of primary bovine mammary cells through various stages of cell subculture. The 1 cm3 pieces of mammary tissues were incubated onto a 10-cm cell culture dish until the cells grow out from the tissues. After the removal of mammary tissues, primary bovine mammary cells (fibroblasts, FBs; myoepithelial cells, MCs; epithelial cells, ECs) were isolated and purified through their different trypsin sensitivity. The primary bovine mammary cells were cultured with control culture media (CCM; without hormones) and differentiation culture media (DCM; with prolactin, insulin, cortisol, progesterone, 17b-estradiol, and epidermal growth factor). At passage 1, FBs, MCs, and ECs cultured with CCM displayed the highest levels of vimentin, α-smooth muscle actin, and cytokeratin 18/19 expression, respectively (p < 0.001). These cellular characteristics were not consistently maintained across subsequent passages, with a notable reduction in cell numbers (p < 0.001). At passage 1, ECs cultured in DCM exhibited higher milk component productivity in comparison to those cultured in CCM (p < 0.05). However, the synthesis of milk components exhibited a gradual decline as vacuoles increased in ECs throughout consecutive passaging. ECs cultured with CCM were unable to synthesize milk components due to the loss of tight junctions caused by matrix metalloproteinase activation. Conversely, ECs cultured with DCM boosted milk component production by intact tight junctions and low matrix metalloproteinase activity (p < 0.05). Our findings demonstrated the requirement for various hormones to maintain the productivity of primary bovine mammary cells over successive passages. These results highlight the importance of hormonal optimization to establish the stable primary cells in cell-cultured milk production.

Cytotoxicity, Antiadipogenic, Low-Density Lipoprotein Oxidation Inhibitory Activities, and Acute Toxicity Study of Psychotria densinervia Hydroethanolic Leaf and Bark Extracts

Background: Obesity is increasingly taking an important stage as a cause of death worldwide, and interventions with a good cost-effectiveness ratio are needed. Psychotria densinervia is one of these natural products with health benefits. Objective. The present study evaluated the cytotoxicity, antiadipogenic, low-density lipoprotein (LDL), oxidation inhibitory activities, and acute toxicity of Psychotria densinervia hydroethanolic leaf and bark extracts. Methods: The cytotoxicity evaluation of the extracts (62.5, 125, 250, and 500 μg/mL) using the MTT assay and the antiadipogenic activity (25, 50, 100, and 200 μg/mL) using oleic acid were carried out in SW-872 cells. Copper sulfate (CuSO4)-induced oxidation was used in the evaluation of the effect of extracts (0.25, 0.5, and 1 mg/mL) against LDL oxidation. The oral acute toxicity evaluation of a single dose of 2000 mg/kg of the extracts was performed in Wistar albino rats weighing 127 ± 2 g. Results: The leaf and bark extracts did not show any sign of cytotoxicity at the tested concentrations. The best antiadipogenic activity was observed by the standard orlistat (38.45 ± 1.70 μg/mL), followed by the leaf extract (IC50: 41.47 ± 0.50 μg/mL) and the least the bark extract (IC50: 107.50 ± 0.90 μg/mL). At a concentration of 1 mg/mL, the leaf extract presented an oxidation lag time of 130 min, which was higher and better than that of the bark extract (120 min). Quercetin (standard) presented an oxidation lag time longer than 3 h. The oral acute toxicity evaluation did not show any signs of toxicity indicating that the LD50 was greater than 2000 mg/kg. Conclusion: Based on the results obtained, the P. densinervia hydroethanolic leaf extract possesses a better antioxidant and antiadipogenic activities than the bark extract.

The interaction of breastfeeding and genetic factors on childhood obesity

Childhood obesity represents a pressing global public health concern due to its widespread prevalence and its close connection to early-life exposure to risk factors. The onset of obesity is contingent upon the interplay of genetic composition, lifestyle choices, and environmental as well as nutritional elements encountered during both fetal development and early childhood. This paper critically examines research discoveries in this area and concisely outlines the influence of breastfeeding on genetic predispositions associated with childhood obesity. Studies have demonstrated that breastfeeding has the potential to reduce childhood obesity by impacting anthropometric indicators. Moreover, the duration of breastfeeding is directly correlated with the degree to which it alters the risk of childhood obesity. Current explorations into the link between genetic factors transmitted through breast milk and childhood obesity predominantly focus on genes like FTO, Leptin, RXRα, PPAR-γ, and others. Numerous research endeavors have suggested that an extended period of exclusive breastfeeding is tied to a diminished likelihood of childhood obesity, particularly if sustained during the initial six months. The duration of breastfeeding also correlates with gene methylation, which could serve as the epigenetic mechanism underpinning breastfeeding's preventative influence against obesity. In summary, the thorough evaluation presented in this review underscores the intricate nature of the association between breastfeeding, genetic factors, and childhood obesity, providing valuable insights for future research efforts and policy formulation.

Current status and challenges for cell-cultured milk technology: a systematic review

Cellular agriculture is an innovative technology for manufacturing sustainable agricultural products as an alternative to traditional agriculture. While most cellular agriculture is predominantly centered on the production of cultured meat, there is a growing demand for an understanding of the production techniques involved in dairy products within cellular agriculture. This review focuses on the current status of cellular agriculture in the dairy sector and technical challenges for cell-cultured milk production. Cellular agriculture technology in the dairy sector has been classified into fermentation-based and animal cell culture-based cellular agriculture. Currently, various companies synthesize milk components through precision fermentation technology. Nevertheless, several startup companies are pursuing animal cell-based technology, driven by public concerns regarding genetically modified organisms in precision fermentation technology. Hence, this review offers an up-to-date exploration of animal cell-based cellular agriculture to produce milk components, specifically emphasizing the structural, functional, and productive aspects of mammary epithelial cells, providing new information for industry and academia.

The medicalization of ethics or ethicalization of neuroscience: Toward a conceptual re-examination

Thinking With a growing body of brain science, the research and technological interventions in neuroscience have led to the rise of some ethical, moral, legal, conceptual, and socioeconomic problems. These problems and the need to establish an intellectual framework to approach them framed the base of Neuroethics. Most conveniently, the normative definition of Neuroethics is declared as ethics of neuroscience and neuroscience of ethics. However, there are more critical issues to define and frame the conceptual structure of the field. The current naturalist-positivist vision in neuroscience will extend the concept that human behavior, such as decision-making, consciousness, character, and moral intuitions, are mechanical features of a machine. Arguments from philosophical and anthropological views arose around this definition, focusing on the reductionist nature of merely a positive view of the human mind and behavior. Thinking through the pearls of such an approach and what would be at stake if we fail to recognize the importance of the philosophical-anthropological aspect of neuroscience, we first review different definitions and critics of the field, then proceed to discuss two concepts of Ethicalization and Medicalization. These concepts clearly show the established positivist-naturalist view in bioethics and the issues it caused. To better understand these two concepts, we use existing discussions and literature around them in bioethics. By reviewing the existing literature and adding a philosophical view of the field, we aim to add a new approach to the field of Neuroethics. We focus on adopting an interdisciplinary approach to Neuroethics to provide the needed background vision and theory to discuss interdisciplinary issues and enable scholars and theorists to reframe the fundamental issues of the field, such as the nature and scope of Neuroethics.

Anesthetic management of a dog undergoing unilateral adrenalectomy for phaeochromocytoma excision using a partial intravenous anesthetic protocol

Background

The anesthetic management of adrenalectomies for phaeochromocytoma excision, a catecholamine-secreting tumor, is challenging due to the potential for fatal complications following severe hemodynamic variations, including hypertensive crisis following tumor manipulation or sympathetic stimulation, but also severe hypotension and volume depletion post resection.

Case Description

An 11 kg, 15-year-old male neutered Jack Russel Terrier, with mitral valve disease stage B2, was referred for adrenalectomy for phaeochromocytoma resection. The patient was administered per os prazosin 0.11 mg/kg twice a day and amlodipine 0.125 mg/kg once a day for preoperative stabilization. On the day of surgery, the dog received maropitant 1 mg/kg intravenously (IV) and was premedicated with 0.2 mg/kg methadone IV. Anesthesia was induced with alfaxalone 1 mg/kg IV and midazolam 0.2 mg/kg IV and maintained with partial intravenous anesthesia using sevoflurane in 70% oxygen and constant rate infusions of dexmedetomidine 0.5 μg/kg/hour and maropitant 100 μg/kg/hour. After induction of anesthesia, the dog was mechanically ventilated, and a transversus abdominal plane block was performed with ropivacaine 0.2%. The dog remained remarkably stable with a single, self-limiting, hypertension episode recorded intraoperatively. Postoperative rescue analgesia consisted of methadone and ketamine. The dog was discharged 48 hours after surgery, but persistent hypertension was reported at suture removal.

Conclusion

The use of a low-dose dexmedetomidine CRI, a maropitant CRI, and a transversus abdominal plane block provided stable perioperative hemodynamic conditions for phaeochromocytoma excision in a dog.

Bovine mammary epithelial cells can grow and express milk protein synthesis genes at reduced fetal bovine serum concentration

Milk proteins produced by lactating cells isolated from bovine mammary tissue can offer a sustainable solution to the high protein demand of a global growing population. Serum is commonly added to culture systems to provide compounds necessary for optimal growth and function of the cells. However, in a cellular agricultural context, its usage is desired to be decreased. This study aims at examining the minimum level of fetal bovine serum (FBS) required for the growth and functionality of bovine mammary epithelial cells (MECs). The cells were isolated from dairy cows in early and mid-lactation and cultured in reduced concentrations of FBS (10%, 5%, 1.25%, and 0%). Real-time cell analysis showed a significant effect of lactation stage on growth rate and 5% FBS resulted in similar growth rate as 10% while 0% resulted in the lowest. The effect of reducing FBS on cell functionality was examined by studying the expressions of selected marker genes involved in milk protein and fat synthesis, following differentiation. The gene expressions were not affected by the level of FBS. A reduction of FBS in the culture system of MEC, at least down to 5%, does not assert any negative effect on the growth and expression levels of studied genes. As the first attempt in developing an in-vitro model for milk component production using MEC, our results demonstrate the potential of MEC to endure FBS-reduced conditions.

Lithium Chloride Promotes Endogenous Synthesis of CLA in Bovine Mammary Epithelial Cells

Although conjugated linoleic acid (CLA) can promote human health, its content in milk is insufficient to have a significant impact. The majority of the CLA in milk is produced endogenously by the mammary gland. However, research on improving its content through nutrient-induced endogenous synthesis is relatively scarce. Previous research found that the key enzyme, stearoyl-CoA desaturase (SCD) for the synthesis of CLA, can be expressed more actively in bovine mammary epithelial cells (MAC-T) when lithium chloride (LiCl) is present. This study investigated whether LiCl can encourage CLA synthesis in MAC-T cells. The results showed that LiCl effectively increased SCD and proteasome α5 subunit (PSMA5) protein expression in MAC-T cells as well as the content of CLA and its endogenous synthesis index. LiCl enhanced the expression of proliferator-activated receptor-γ (PPARγ), sterol regulatory element-binding protein 1 (SREBP1), and its downstream enzymes acetyl CoA carboxylase (ACC), fatty acid synthase (FASN), lipoprotein lipase (LPL), and Perilipin 2 (PLIN2). The addition of LiCl significantly enhanced p-GSK-3β, β-catenin, p-β-catenin protein expression, hypoxia-inducible factor-1α (HIF-1α), and downregulation factor genes for mRNA expression (P < 0.05). These findings highlight that LiCl can increase the expression of SCD and PSMA5 by activating the transcription of HIF-1α, Wnt/β-catenin, and the SREBP1 signaling pathways to promote the conversion of trans-vaccenic acid (TVA) to the endogenous synthesis of CLA. This data suggests that the exogenous addition of nutrients can increase CLA content in milk through pertinent signaling pathways.

Phyto-fabrication of ultrafine nanoscale holmium oxide HT-Ho2O3 NPs and their biomedical potential

In this study holmium oxide nanoparticles (Ho2O3 NPs) are fabricated using Hyphaene thebaica extracts as a bioreductant. The XRD pattern of HT-Ho2O3 NPs (product from phyto-reduction) suggested that the nanoparticles are crystalline with no impurities. Scherrer approximation revealed grain sizes of ∼10 nm. The HR-TEM revealed HT-Ho2O3 NPs possessed a quasi-spherical morphology complemented by SEM and the particle sizes were in the range of 6-12 nm. The infrared spectra revealed characteristic Ho-O bonding at ∼603 cm-1. Raman spectra indicated five main peaks positioned at 156 cm-1, 214 cm-1, 328 cm-1, 379 cm-1 and 607 cm-1. Eg (optical bandgap) was found to be 5.1 eV. PL spectra indicated two major peaks at 415 nm and 607 nm. EDS spectra confirmed the elemental presence of holmium (Ho). Spotty rings were obtained during the SAED measurement which indicated crystallinity of HT-Ho2O3 NPs. The HT-Ho2O3 NPs were further analyzed for their antioxidant, anti-angiogenic and cytotoxic properties. The antioxidant potential was moderate i.e., 43.40 ± 0.96% at 1000 μg mL-1 which decreased in a dose dependent manner. Brine shrimp lethality was highest at 1000 μg mL-1 with the LC50 320.4 μg mL-1. Moderate anti-angiogenic potential was observed using in ova CAM assay. MTT bioassay revealed that the HT-Ho2O3 NPs inhibited the 3T3 cells (IC50 67.9 μg mL-1), however, no significant inhibition was observed against MCF-7 cells. α-Amylase and β-glucosidase inhibition revealed that the HT-Ho2O3 NPs can be of use in controlling blood glucose levels. Overall, it can be concluded that biosynthesis using aqueous extracts can be a suitable alternative in finding ecofriendly paradigms for the synthesis of nanoparticles. We suggest extended research into the bioreduced Ho2O3 NPs for establishing their biomedical potential and toxicity.

Adipocyte-Derived Paracrine Factors Regulate the In Vitro Development of Bovine Mammary Epithelial Cells

The mammary gland is composed of epithelial tissue forming ducts and lobules, and the stroma, composed of adipocytes, connective tissue, and other cell types. The stromal microenvironment regulates mammary gland development by paracrine and cell-cell interactions. In the present study, primary cultures of bovine mammary epithelial cells (bMEC) and bovine adipose-derived stem cells (bASC) subjected to adipogenic differentiation were used to investigate the influence of paracrine factors secreted by preadipocytes and adipocytes on bMEC development. Four types of conditioned media (CM) were collected from undifferentiated preadipocytes (preA) and adipocytes on days: 8, 12, 14 of differentiation. Next, bMEC were cultured for 24 h in CM and cell viability, apoptosis, migratory activity, ability to form spheroids on Matrigel, and secretory activity (alpha S1-casein concentration) were evaluated. CM derived from fully differentiated adipocytes (12 d and 14 d) significantly decreased the number of apoptotic cells in bMEC population and increased the size of spheroids formed by bMEC on Matrigel. CM collected from preadipocytes significantly enhanced bMEC's migration, and stimulated bMEC to produce alpha S1-casein, but only in the presence of prolactin. These results confirm that preadipocytes and adipocytes are important components of the stroma, providing paracrine factors that actively regulate the development of bovine mammary epithelium.

Genome-wide identification of bovine ADAMTS gene family and analysis of its expression profile in the inflammatory process of mammary epithelial cells

ADAM metallopeptidase with thrombospondin type 1 motif (ADAMTS) are secreted, multi-domain matrix-related zinc endopeptidases that play a role in organogenesis, assembly and degradation of extracellular matrix (ECM), cancer and inflammation. Genome-wide identification and analysis of the bovine ADAMTS gene family has not yet been carried out. In this study, 19 ADAMTS family genes were identified in Bos taurus by genome-wide bioinformatics analysis, and they were unevenly distributed on 12 chromosomes. Phylogenetic analysis shows that the Bos taurus ADAMTS are divided into eight subfamilies, with highly consistent gene structures and motifs within the same subfamily. Collinearity analysis showed that the Bos taurus ADAMTS gene family is homologous to other bovine subfamily species, and many ADAMTS genes may be derived from tandem replication and segmental replication. In addition, based on the analysis of RNA-seq data, we found the expression pattern of ADAMTS gene in different tissues. Meanwhile, we also analyzed the expression profile of ADAMTS gene in the inflammatory response of bovine mammary epithelial cells (BMECs) stimulated by LPS by qRT-PCR. The results can provide ideas for understanding the evolutionary relationship and expression pattern of ADAMTS gene in Bovidae, and clarify the theoretical basis of the function of ADAMTS in inflammation.

Comprehensive landscape and future perspectives of long noncoding RNAs (lncRNAs) in colorectal cancer (CRC): Based on a bibliometric analysis

This review aimed to use bibliometric analysis to sort out, analyze and summarize the knowledge foundation and hot topics in the field of long noncoding RNAs (lncRNAs) in colorectal cancer (CRC), and point out future trends to inspire related research and innovation. We used CiteSpace to analyze publication outputs, countries, institutions, authors, journals, references, and keywords. Knowledge foundations, hotspots, and future trends were then depicted. The overall research showed the trend of biomedical-oriented multidisciplinary. Much evidence indicates that lncRNA plays the role of oncogene or tumor suppressor in the occurrence and development of CRC. Besides, many lncRNAs have multiple mechanisms. lncRNAs and metastasis of CRC, lncRNAs and drug resistance of CRC, and the clinical application of lncRNAs in CRC are current research hotspots. Through insight into the development trend of lncRNAs in CRC, this study will help researchers extract hidden valuable information for further research.

A software tool for data mining of physicochemical properties of peptides

Biologically active peptides (BAP) are increasingly in the focus of scientific research due to their widespread use in medicine, food and pharmaceutical industries. Researching and studying the properties of peptides is a laborious and expensive process. In recent years, in silico methods, including data mining or artificial intelligence, have been applied more and more to reveal biological, physicochemical and sensory properties of peptides. This significantly shortens the process of peptide sequences analysis. This article presents a software tool that uses a data mining approach to discover a number of physicochemical properties of a specific peptide. Working with it is extremely simple - it is only necessary to input the amino acid sequence of the peptide of interest. The software tool is designed to generate data in order to increase the classification and prediction accuracy, as well as to leverage the engineering of new amino acid sequences. This way, the proposed software greatly facilitates the work or scientific researchers. The software application is publicly available at www.pep-lab.info/dmpep.

Molecular Hydrogen as a Medical Gas for the Treatment of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Possible Efficacy Based on a Literature Review

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disorder that is characterized by fatigue that persists for more than 6 months, weakness, sleep disturbances, and cognitive dysfunction. There are multiple possible etiologies for ME/CFS, among which mitochondrial dysfunction plays a major role in abnormal energy metabolism. The potential of many substances for the treatment of ME/CFS has been examined; however, satisfactory outcomes have not yet been achieved. The development of new substances for curative, not symptomatic, treatments is desired. Molecular hydrogen (H2) ameliorates mitochondrial dysfunction by scavenging hydroxyl radicals, the most potent oxidant among reactive oxygen species. Animal experiments and clinical trials reported that H2 exerted ameliorative effects on acute and chronic fatigue. Therefore, we conducted a literature review on the mechanism by which H2 improves acute and chronic fatigue in animals and healthy people and showed that the attenuation of mitochondrial dysfunction by H2 may be involved in the ameliorative effects. Although further clinical trials are needed to determine the efficacy and mechanism of H2 gas in ME/CFS, our literature review suggested that H2 gas may be an effective medical gas for the treatment of ME/CFS.

Toxicity and mechanism of mesoporous silica nanoparticles in eyes

The study on the safety of nanomaterials in eyes is still in its early stages. In this study, we put our focus on the effect of one important nanoparticle feature - large surface area - to assess eye safety. To this end, mesoporous silica nanoparticles (MSiNPs) were for the first time employed as a model to evaluate their toxicity in eyes. The porosity of the MSiNPs endows them with a large surface area and the ability to attach to surrounding chemical or biological molecules, further enhancing their surface reactivity and toxic effects. Therefore, to better mimic MSiNP exposure in real environments, we also introduced other hazardous substances such as silver ions (Ag+) to the system and then investigated their synergistic nanotoxicity. Our results showed that the exposure to MSiNPs-Ag+ and even Ag+ at a safe dose, resulted in more significant toxicity than the MSiNPs alone, as evidenced from cell viability, apoptosis, reactive oxygen species (ROS) production, and DNA damage experiments. RNA-Sequencing analysis revealed that the mRNA surveillance signalling pathway plays a unique role in regulating MSiNPs-Ag+-induced cytotoxicity. Besides this, severe corneal damage and dry eye were observed in rat models upon exposure to MSiNPs-Ag+ compared to MSiNPs. Most importantly, we also proposed a protein corona-based therapy to treat MSiNP-induced corneal disease, where the corneal damage could be rescued by fetal bovine serum (FBS) treatment.

Milk cholesterol concentration in mice is not affected by high cholesterol diet- or genetically-induced hypercholesterolaemia

Breast milk cholesterol content may imply to affect short- and long-term cholesterol homeostasis in the offspring. However, mechanisms of regulating milk cholesterol concentration are only partly understood. We used different mouse models to assess the impact of high cholesterol diet (HC)- or genetically-induced hypercholesterolaemia on milk cholesterol content. At day 14 postpartum we determined milk, plasma and tissue lipids in wild type (WT), LDL receptor knockout (Ldlr−/−), and ATP-binding cassette transporter G8 knockout (Abcg8−/−) mice fed either low- or 0.5% HC diet. In chow-fed mice, plasma cholesterol was higher in Ldlr−/− dams compared to WT. HC-feeding increased plasma cholesterol in all three models compared to chow diet. Despite the up to 5-fold change in plasma cholesterol concentration, the genetic and dietary conditions did not affect milk cholesterol levels. To detect possible compensatory changes, we quantified de novo cholesterol synthesis in mammary gland and liver, which was strongly reduced in the various hypercholesterolaemic conditions. Together, these data suggest that milk cholesterol concentration in mice is not affected by conditions of maternal hypercholesterolaemia and is maintained at stable levels via ABCG8- and LDLR-independent mechanisms. The robustness of milk cholesterol levels might indicate an important physiological function of cholesterol supply to the offspring.

In vitro characterization and endocrine regulation of cholesterol and phospholipid transport in the mammary gland

Cell-based studies previously showed that the ATP-binding cassette transporter A1 (ABCA1) transfers cholesterol across mammary epithelial cells (MEC). Data for phospholipid transport are lacking, and it is unclear from which cellular source the transported cholesterol stems, whether this transport activates signaling pathways, and how lactogenic hormones regulate it. To clarify these aspects, lipid transport and expressional analyses were performed in bovine primary (bMEC) and/or immortalized (MAC-T) MEC cultures. Lipid efflux and ABCA1, ABCG1 and liver X receptorα mRNA levels were higher in MAC-T than bMEC. In MAC-T, the transported cholesterol originated mainly from the plasma membrane. ABCA1 dependent cholesterol efflux was higher than phosphatidylcholine efflux, was suppressed by probucol (ABCA1 inhibitor), AG490 (janus kinase-2 inhibitor), PD98059 (mitogen activated protein kinase kinase inhibitor) and pretreatment with β-cyclodextrin (lowering membrane cholesterol). Insulin was the only hormone significantly increasing cholesterol efflux. In conclusion, this study gives novel mechanistic and regulatory insights into the transport of cholesterol and phospholipids in MEC.

Mammary Epithelial Cell Hierarchy in the Dairy Cow Throughout Lactation

The plasticity of the mammary gland relies on adult mammary stem cells (MaSCs) and their progenitors, which give rise to various populations of mammary epithelial cells (MECs). To face global challenges, an in-depth characterization of milk-producing animal mammary gland plasticity is required, to select more sustainable and robust dairy cows. The identification and characterization of MaSC and their progenitors will also provide innovative tools in veterinary/human medicine regarding mammary tissue damage (carcinogenesis, bacterial infections). This study aimed to determine the dynamics of mammary cell populations throughout a lactation cycle. Using mammary biopsies from primiparous lactating dairy cows at 30, 90, 150, and 250 days of lactation, we phenotyped cell populations by flow cytometry. To investigate cell lineages, we used specific cell-surface markers, including CD49f, CD24, EpCAM (epithelial cell adhesion molecule), and CD10. Two cell populations linked to milk production were identified: CD49f(+)/EpCAM(-) (y = 0.88x + 4.42, R(2) = 0.36, P < 0.05) and CD49f(-)/EpCAM(-) (y = -1.15x + 92.44, R(2) = 0.51, P < 0.05) cells. Combining immunostaining analysis, flow cytometry, daily milk production data, and statistical approaches, we defined a stem cell population (CD24(+)/CD49f(+)) and four progenitor cell populations that include bipotent luminal progenitors (CD24(-)/CD49f(+)), lumino-alveolar progenitors (CD24(-)/EpCAM(+)), myoepithelial progenitors (CD24(+)/CD10(-)), and lumino-ductal progenitors (CD49f(-)/EpCAM(+)). Interestingly, we found that the bipotent luminal progenitors (CD24(-)/CD49f(+)) decreased significantly (P < 0.05) during lactation. This study provides the first results of mammary cell lineage, allowing insight into mammary cell plasticity during lactation.