Exocrine gland structure-function relationships.

Fluid secretion by exocrine glandular organs is essential to the survival of mammals. Each glandular unit within the body is uniquely organized to carry out its own specific functions, with failure to establish these specialized structures resulting in impaired organ function. Here, we review glandular organs in terms of shared and divergent architecture. We first describe the structural organization of the diverse glandular secretory units (the end-pieces) and their fluid transporting systems (the ducts) within the mammalian system, focusing on how tissue architecture corresponds to functional output. We then highlight how defects in development of end-piece and ductal architecture impacts secretory function. Finally, we discuss how knowledge of exocrine gland structure-function relationships can be applied to the development of new diagnostics, regenerative approaches and tissue regeneration.

Breast milk transmission and involvement of mammary glands in tick-borne flavivirus infected mice.

Tick-borne flaviviruses (TBFs) are transmitted to humans through milk and tick bites. Although a case of possible mother-to-child transmission of tick-borne encephalitis virus (TBEV) through breast milk has been reported, this route has not been confirmed in experimental models. Therefore, in this study, using type I interferon receptor-deficient A129 mice infected with Langat virus (LGTV), we aimed to demonstrate the presence of infectious virus in the milk and mammary glands of infected mice. Our results showed viral RNA of LGTV in the pup's stomach milk clots (SMCs) and blood, indicating that the virus can be transmitted from dam to pup through breast milk. In addition, we observed that LGTV infection causes tissue lesions in the mammary gland, and viral particles were present in mammary gland epithelial cells. Furthermore, we found that milk from infected mice could infect adult mice via the intragastric route, which has a milder infection process, longer infection time, and a lower rate of weight loss than other modes of infection. Specifically, we developed a nano-luciferase-LGTV reporter virus system to monitor the dynamics of different infection routes and observed dam-to-pup infection using in vivo bioluminescence imaging. This study provides comprehensive evidence to support breast milk transmission of TBF in mice and has helped provide useful data for studying TBF transmission routes.IMPORTANCETo date, no experimental models have confirmed mother-to-child transmission of tick-borne flavivirus (TBF) through breastfeeding. In this study, we used a mouse model to demonstrate the presence of infectious viruses in mouse breast milk and mammary gland epithelial cells. Our results showed that pups could become infected through the gastrointestinal route by suckling milk, and the infection dynamics could be monitored using a reporter virus system during breastfeeding in vivo. We believe our findings have provided substantial evidence to understand the underlying mechanism of breast milk transmission of TBF in mice, which has important implications for understanding and preventing TBF transmission in humans.

Transcriptomic analysis reveals molecular insights into lactation dynamics in Jakhrana goat mammary gland.

BACKGROUND: Goat milk is gaining popularity as a superior alternative to bovine milk due to its closer resemblance to human milk. Understanding the molecular processes underlying lactation is crucial for improving milk quality and production in goats. However, the genetic mechanisms governing lactation in goats, particularly in indigenous breeds like the Jakhrana, remain largely unexplored. RESULTS: In this study, we performed a comprehensive transcriptomic analysis of Jakhrana goat mammary glands during early and late lactation stages. We isolated milk somatic cells and conducted RNA sequencing, followed by transcript quantification and mapping against the ARS1.2 Capra hircus reference assembly. Our analysis identified differentially expressed genes (DEGs) and commonly expressed genes (CEGs) across the lactation phases. Early lactation showed enrichment of genes encoding antimicrobial peptides and lubrication proteins, while late lactation exhibited heightened expression of genes encoding major milk proteins. Additionally, DEG analysis revealed upregulation of pivotal genes, such as the ABC transporter gene MRP4, implicated in modulating milk composition and quality. CONCLUSION: Our findings provide insights into the genetic mechanisms underlying lactation dynamics in the Jakhrana goat. Understanding these mechanisms could help in improving milk production and quality in goats, benefiting both the dairy industry and consumers.

Evaluation of breast skin and tissue stiffness using a non-invasive aspiration device and impact of clinical predictors.

A personalized 3D breast model could present a real benefit for preoperative discussion with patients, surgical planning, and guidance. Breast tissue biomechanical properties have been poorly studied in vivo, although they are important for breast deformation simulation. The main objective of our study was to determine breast skin thickness and breast skin and adipose/fibroglandular tissue stiffness. The secondary objective was to assess clinical predictors of elasticity and thickness: age, smoking status, body mass index, contraception, pregnancies, breastfeeding, menopausal status, history of radiotherapy or breast surgery. Participants were included at the Montpellier University Breast Surgery Department from March to May 2022. Breast skin thickness was measured by ultrasonography, breast skin and adipose/fibroglandular tissue stiffnesses were determined with a VLASTIC non-invasive aspiration device at three different sites (breast segments I-III). Multivariable linear models were used to assess clinical predictors of elasticity and thickness. In this cohort of 196 women, the mean breast skin and adipose/fibroglandular tissue stiffness values were 39 and 3 kPa, respectively. The mean breast skin thickness was 1.83 mm. Only menopausal status was significantly correlated with breast skin thickness and adipose/fibroglandular tissue stiffness. The next step will be to implement these stiffness and thickness values in a biomechanical breast model and to evaluate its capacity to predict breast tissue deformations.

Comorbid pathology of the mammary glands and endometriosis: risk factors and prognosis.

OBJECTIVE: Aim: based on a retrospective analysis, the relationship between external genital endometriosis and comorbid breast pathology was established and risk factors were identified, their comparison and the formation of a prognostic risk criterion were determined. PATIENTS AND METHODS: Materials and Methods: to address the objectives of the study, a retrospective analysis of 470 cases of patients treated for external genital endometriosis after surgical treatment and comorbid breast pathology was conducted. The control group included 30 healthy non-pregnant women. Statistical processing was performed on a personal computer using the statistical software package Statistica 10. RESULTS: Results: As a result of the analysis, the age of the patients ranged from 23 to 40 years. The average age of patients in the study group was (32.2}1.18) years, and in the control group (31.1}1.35) (p>0.05). The groups were homogeneous in terms of age (p>0.05), marital status (p>0.05) and level of education (p>0.05). Close relatives in 208 (44.25}2.18) % (OR=8.86; 95 % CI: (0.68-10.53); p<0.002) cases suffered from benign (hormone-dependent) tumours and tumour-like diseases of the uterus and appendages in isolation or in various combinations (fibroids, adenomyosis, endometrial hyperplasia). It was also found that 102 (21.70}1.67) % of patients had endometriosis, which may indicate a genetic predisposition to this disease. In the closest relatives of EM patients: in 118 (25.10}2.01) % of the examined parents, breast problems were noted, in 66 (14.04}1.12) % - diabetes mellitus, and in 98 (20.85}1.22) % thyroid diseases were detected, which in total amounted to (60.00}2.23) % (OR=9.12; 95 % CI: (0.58-11.54); p<0.002). Early menarche almost tripled the risk of EM (OR=2.72; 95% CI: (1.02-5.11); p<0.002), and menstrual irregularities doubled it (OR=2.04; 95% CI: (1.09-3.14); p<0.05), higher education, urban residents - 2.2 times higher (OR= 2.27; 95 % CI: (1.11-3.63); p<0.05), diseases of the gastrointestinal tract and hepatobiliary complex - 5.2 times higher (OR=5.27; 95 % CI: (1.89-12.03); p<0.05), frequently recurrent inflammatory diseases of the appendages - 3 times higher (OR=3.14; 95 % CI: (0.91-5.14); p<0.05), dysmetabolic manifestations (thyroid dysfunction) - 5 times higher (OR=5.11; 95 % CI: (1.61-9.503); p<0.002). CONCLUSION: Conclusions: Thus, in endometriosis and dyshormonal diseases of the mammary glands, menstrual and generative function disorders, along with clinical symptoms of pelvic pain, dysmenorrhoea, autonomic nervous system disorders and sexual dysfunction, are significant components of this problem, initiating comorbidity processes in target organs in the setting of hormonal maladaptation. Therefore, these comorbidities become a trigger for the activation of systemic hormonal imbalance and become an urgent interdisciplinary problem that requires further study.

Effects of silver nanoparticles on maternal mammary glands and offspring development under lactation exposure.

The widespread applications of silver nanoparticles (AgNPs) throughout our daily lives have raised concerns regarding their environmental health and safety (EHS). Despite an increasing number of studies focused on the EHS impacts of AgNPs, there remain significant knowledge gaps with respect to their potential health impacts on susceptible populations, such as lactating mothers and infants. Herein, we aimed to investigate the deleterious effects of AgNPs with different sizes (20 and 40 nm) and surface coatings (PVP and BPEI) on maternal mice and their offspring following lactation exposure at doses of 20, 100 and 400 µg/kg body weight. We discovered that AgNPs could accumulate in the maternal mammary glands and disrupt the epithelial barrier in a dose-dependent manner. Notably, BPEI-coated AgNPs caused more damage to the mammary glands than PVP-coated particles. Importantly, we observed that, while AgNPs were distributed throughout the blood and main tissues, they were particularly enriched in the brains of breastfed offspring after maternal exposure during lactation, exhibiting exposure dosage- and particle coating-dependent patterns. Compared to PVP-coated nanoparticles, BPEI-coated AgNPs were more readily transferred to the offspring, possibly due to their enhanced deposition in maternal mammary glands. Moreover, we observed reduced body weight, blood cell toxicity, and tissue injuries in breastfed offspring whose dams received AgNPs. As a whole, these results reveal that maternal exposure to AgNPs results in the translocation of AgNPs into offspring via breastfeeding, inducing developmental impairments in these breastfed offspring. This study provides important new insights into the EHS impacts of AgNP consumption during lactation.

miR-30a-3p Regulates Autophagy in the Involution of Mice Mammary Glands.

The mammary gland undergoes intensive remodeling during the lactation cycle, and the involution process of mammary gland contains extensive epithelial cells involved in the process of autophagy. Our studies of mice mammary glands suggest that miR-30a-3p expression was low during involution compared with its high expression in the mammary glands of lactating mice. Then, we revealed that miR-30a-3p negatively regulated autophagy by autophagy related 12 (Atg12) in mouse mammary gland epithelial cells (MMECs). Restoring ATG12, knocking down autophagy related 5 (Atg5), starvation, and Rapamycin were used to further confirm this conclusion. Overexpression of miR-30a-3p inhibited autophagy and altered mammary structure in the involution of the mammary glands of mice, which was indicative of alteration in mammary remodeling. Taken together, these results elucidated the molecular mechanisms of miR-30a-3p as a key induction mediator of autophagy by targeting Atg12 within the transition period between lactation and involution in mammary glands.

[Research progress on traditional Chinese medicine compounds combined with external therapy in treatment of hyperplasia of mammary glands].

Hyperplasia of mammary glands is a benign breast disease with disordered breast structure. Nowadays, the incidence rate of breast hyperplasia in women is increasing year by year, and the etiology is related to the imbalance of estrogen and progesterone in the body. The symptoms include breast pain, breast nodules, or nipple discharge, which can develop into breast cancer in the context of psychological pressure. Therefore, it is timely and effectively necessary for people to treat the symptoms. At present, traditional Chinese medicine(TCM) often treats breast hyperplasia by oral drug, external application, acupuncture, moxibustion, and massage, while western medicine often uses hormone therapy or surgery. TCM can regulate hormone levels to treat breast hyperplasia. Acupuncture, moxibustion, and other methods can stimulate acupoints to reduce breast lumps. However, since TCM is easy to produce hepatorenal toxicity after long-term use and simple external treatment is slow to take effect, rapid and effective treatment is difficult to be achieved. Although western medicine can inhibit the disease, it is easy to produce toxic and side effects if taken for a long time. In addition, surgery can only remove the focus and the recurrence rate is high. Some studies have found that the combination of oral and external use of TCM compounds has a significant effect, with mild toxic and side effects, few adverse reactions, and a low recurrence rate. Based on the relevant literature in recent years, this article reviewed the combination of oral and external treatment of TCM in the treatment of hyperplasia of mammary glands, discussed the effectiveness, clinical evaluation indexes, and mechanism, and pointed out the existing shortcomings to explore a comprehensive therapy worthy of clinical application.

[Mechanism of blood-activating and mass-dissipating Chinese patent medicine against hyperplasia of mammary glands and use with other medicine: a review].

Caused by endocrine disorder, hyperplasia of mammary glands(HMG) tends to occur in the young with increasing incidence, putting patients at the risk of cancer and threatening the health of women. Therefore, the prevention and treatment of HMG is attracting more and more attention. Amid the modernization of traditional Chinese medicine(TCM), many scholars have found that Chinese patent medicine has unique advantages and huge potential in treatment of endocrine disorder. Particularly, Chinese patent medicine with the function of blood-activating and mass-dissipating, such as Xiaojin Pills and Xiaozheng Pills, has been commonly used in clinical treatment of HMG, which features multiple targets, obvious efficacy, small side effect, and ease of taking and carrying around. Clinical studies have found that the combination of Chinese patent medicine with other medicine can not only improve the efficacy and relieve symptoms such as hyperplasia and pain but also reduce the toxic and side effects of western medicine. Therefore, based on precious pharmacological research and clinical research, this study reviewed the mechanisms of blood-activating mass-dissipating Chinese patent medicine alone and in combination with other medicine, such as regulating levels of in vivo hormones and receptors, promoting apoptosis, inhibiting angiogenesis, improving hemorheology indexes, enhancing immunity, and boosting antioxidant ability. In addition, limitations and problems were summarized. Thereby, this study is expected to lay a theoretical basis for the further study and clinical application of blood-activating mass-dissipating Chinese patent medicine alone or in combination with other medicine against HMG.

[Mechanism of anti-hyperplasia of mammary glands of Xihuang Pills blood-entering component based on UPLC-Q-TOF-MS and network pharmacology].

In this study, based on network pharmacology and molecular docking method, the mechanism of anti-hyperplasia of mammary glands of Xihuang Pills blood-entering components was explored, and the efficacy and key targets of Xihuang Pills blood-entering components were experimentally verified by MCF-10A proliferation model of human mammary epithelial cells. In order to clarify the material basis and mechanism of Xihuang Pills in realizing anti-hyperplasia of mammary glands, the blood-entering components of Xihuang Pills were qualitatively analyzed by UPLC-Q-TOF-MS, and 22 blood-entering components were identified. By taking the blood-entering components as the research object, the network pharmacology prediction and molecular docking verification were carried out, and finally, three key targets were screened out, namely JAK1, SRC, and CDK1. In vitro experiments show that Xihuang Pills can inhibit the proliferation of MCF-10A cells, promote the apoptosis of MCF-10A cells, and reduce the expression of JAK1, SRC, and CDK1 targets in cells. To sum up, Xihuang Pills can promote the apoptosis of mammary epithelial cells by regulating the expression of JAK1, SRC, and CDK1 and then play an anti-hyperplasia role, which provides an experimental basis for clarifying the material basis of Xihuang Pills for anti-hyperplasia effect.

Sodium Acetate and Sodium Butyrate Differentially Upregulate Antimicrobial Component Production in Mammary Glands of Lactating Goats.

Short-chain fatty acids activate antimicrobial component production in the intestine. However, their effects on mammary glands remain unclear. We investigated the effects of acetate and butyrate on antimicrobial component production in mammary epithelial cells (MECs) or leukocytes cultured in vitro and in mammary glands of lactating Tokara goats in vivo. Our results showed that butyrate enhanced the production of ß-defensin-1 and S100A7 in MECs. Additionally, the infusion of butyrate into mammary glands through the teats enhanced ß-defensin-1 and S100A7 concentrations in milk. The infusion of acetate also increased ß-defensin-1 and S100A7 concentrations along with those of cathelicidin-2 and interleukin-8, which are produced by leukocytes. Furthermore, acetate promoted cathelicidin-2 and interleukin-8 secretion in leukocytes in vitro. These findings suggest that acetate and butyrate differentially upregulate antimicrobial component production in mammary glands, which could help to develop appropriate treatment for mastitis, thereby reducing economic losses and improving animal welfare in farming environments.

Morphological and immunohistochemical characterization and molecular classification of spontaneous mammary gland tumors in macropods.

Mammary gland neoplasms in macropods are uncommonly reported, and the morphological and immunohistochemical characteristics are incompletely described. The goal of this study was to describe the morphologic features of macropod mammary neoplasms and to determine the molecular subtypes of mammary carcinomas using a panel of antibodies against estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (Her-2), p63, smooth muscle actin (SMA), and epidermal growth factor receptor (EGFR). Biopsy and necropsy specimens were examined from 21 macropods with mammary tumors submitted to Northwest ZooPath from 1996 to 2019. In accordance with the histologic classification of canine mammary tumors proposed by Goldschmidt and colleagues, tubulopapillary (2), tubular (10), and comedo-carcinomas (2), adenoma (1), lobular hyperplasia (3), fibroadenomatous hyperplasia (1), and mastitis (2) were diagnosed. Red kangaroos (Osphranter rufus) were most commonly diagnosed with mammary carcinomas (79% of all carcinomas). Seven carcinomas had lymphovascular invasion and 2 also had pulmonary metastases. Six of these 7 carcinomas were classified as grade 3. Immunohistochemistry (IHC) for all antibodies was performed on 9/14 carcinomas, and partial IHC was performed for 3 cases. All 12 carcinomas were immunoreactive for PR, 5 for ER, 9 for EGFR, and none for Her-2. Five of the 9 mammary carcinomas with complete IHC data were classified as luminal A subtype, and 4 were normal-like subtype. Accurate classification of mammary tumors in macropods based on morphology, immunohistological characteristics, and molecular subtype may be helpful in guiding clinical management, prognosis, and potential therapeutic targets.

Side branching and luminal lineage commitment by ID2 in developing mammary glands.

Mammary glands develop through primary ductal elongation and side branching to maximize the spatial area. Although primary ducts are generated by bifurcation of terminal end buds, the mechanism through which side branching occurs is still largely unclear. Here, we show that inhibitor of DNA-binding 2 (ID2) drives side branch formation through the differentiation of K6+ bipotent progenitor cells (BPs) into CD61+ luminal progenitor cells (LPs). Id2-null mice had side-branching defects, along with developmental blockage of the differentiation of K6+ BPs into CD61+ LPs. Notably, CD61+ LPs were found in budding and side branches, but not in terminal end buds. Hormone reconstitution studies using ovariectomized MMTV-hemagglutinin-nuclear localized sequence-tagged Id2 transgenic mice revealed that ID2 is a key mediator of progesterone, which drives luminal lineage differentiation and side branching. Our results suggest that CD61 is a marker of side branches and that ID2 regulates side branch formation by inducing luminal lineage commitment from K6+ BPs to CD61+ LPs.

Assessing amino acid uptake and metabolism in mammary glands of lactating dairy cows intravenously infused with methionine, lysine, and histidine or with leucine and isoleucine.

The objective of this study was to evaluate the effect of jugular infusions of 2 groups of AA on essential AA (EAA) transport and metabolism by mammary glands. Four Holstein cows in second lactation (66 ± 10 d in milk) were used in 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Treatments were jugular infusions of saline; Met, Lys, and His (MKH); Ile and Leu (IL); or MKH plus IL (MKH+IL). Each period consisted of 8 d of no infusion followed by 8 d of jugular vein infusion of the treatment solutions. Amino acids were infused at rates of 21 g of Met, 38 g of Lys, 20 g of His, 50 g of Leu, and 22 g of Ile per day. Cows were fed a basal diet consisting of 15.2% crude protein with adequate rumen degradable protein but 15% deficient in MP based on estimates by Cornell Net Carbohydrate and Protein System (v6.5). On the last day of each period, 13C-AA derived from algae was infused into the jugular vein over 6 h, and blood and milk samples were collected before, during, and after infusion. Plasma and milk samples were analyzed for AA isotopic enrichment, and a mammary compartmental model was fitted to the data to derive bidirectional transport and metabolism rates for individual EAA. Influx of Leu increased with IL, whereas influx of other EAA was not different among treatments. Cellular efflux of Met and Lys to venous plasma represented 12 to 34% of influx, whereas cellular efflux of Phe and BCAA represented 29 to 59% of influx. Increased efflux/influx ratios of Ile and Leu with IL but not Met and Lys with MKH demonstrated that increased Ile and Leu influx was mostly returned to plasma resulting in no change in net uptake or efficiency. The isotope results showed that mammary net uptake of Lys and Ile increased during MKH infusion. Net uptake of Met increased with MKH but only in the absence of IL. Catabolism of Lys and Met only increased with MKH alone, resulting in decreased efficiency for milk protein, which demonstrated that Ile and Leu infusion can spare Lys and Met for milk protein synthesis. Total AA uptake to milk output was not different from 1, implying the catabolized Met and Lys contributed nitrogen to nonessential AA. Overall, EAA uptake and metabolism in mammary glands of dairy cows varied across individual EAA and responded differently to respective AA supplements. In addition, uptake, retention, and end use of AA by mammary tissue is variable and dependent on the mix of AA provided. This variability, depending on the mix of AA absorbed, will change the efficiency of utilization of individual AA at the mammary gland level and consequently the whole-body level. Thus, it is inaccurate to use a fixed, constant efficiency within and across AA to represent tissue activity.

IL-4 and IL-13 Promote Proliferation of Mammary Epithelial Cells through STAT6 and IRS-1.

T helper (Th)2 cytokines such as interleukin (IL)-4 and IL-13 control immune function by acting on leukocytes. They also regulate multiple responses in non-hematopoietic cells. During pregnancy, IL-4 and IL-13 facilitate alveologenesis of mammary glands. This particular morphogenesis generates alveoli from existing ducts and requires substantial cell proliferation. Using 3D cultures of primary mouse mammary epithelial cells, we demonstrate that IL-4 and IL-13 promote cell proliferation, leading to enlargement of mammary acini with partially filled lumens. The mitogenic effects of IL-4 and IL-13 are mediated by STAT6 as inhibition of STAT6 suppresses cell proliferation and improves lumen formation. In addition, IL-4 and IL-13 stimulate tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1). Prolonged treatment with these cytokines leads to increased IRS-1 abundance, which, in turn, amplifies IL-4- and IL-13-stimulated IRS-1 tyrosine phosphorylation. Through signaling crosstalk between IL-4/IL-13 and insulin, a hormone routinely included in mammary cultures, IRS-1 tyrosine phosphorylation is further enhanced. Lowering IRS-1 expression reduces cell proliferation, suggesting that IRS-1 is involved in IL-4- and IL-13-stimulated cell proliferation. Thus, a Th2-dominant cytokine milieu during pregnancy confers mammary gland development by promoting cell proliferation.

Functional Significance of Selective Expression of ERα and ERß in Mammary Gland Organ Culture.

Thoracic pair of mammary glands from steroid hormone-pretreated mice respond to hormones structurally and functionally in organ culture. A short exposure of glands for 24 h to 7,12 Dimethylbenz(a)anthracene (DMBA) during a 24-day culture period induced alveolar or ductal lesions. Methods: To differentiate the functional significance of ERα and ERß, we employed estrogen receptor (ER) knockout mice. We compared the effects of DMBA on the development of preneoplastic lesions in the glands in the absence of ERα (αERKO) and ERß (ßERKO) using an MMOC protocol. Glands were also subjected to microarray analyses. We showed that estradiol can be replaced by EGF for pretreatment of mice. The carcinogen-induced lesions developed under both steroids and EGF pretreatment protocols. The glands from αERKO did not develop any lesions, whereas in ßERKO mice in which ERα is intact, mammary alveolar lesions developed. Comparison of microarrays of control, αERKO and ßERKO mice showed that ERα was largely responsible for proliferation and the MAP kinase pathways, whereas ERß regulated steroid metabolism-related genes. The results indicate that ERα is essential for the development of precancerous lesions. Both subtypes, ERα and Erß, differentially regulated gene expression in mammary glands in organ cultures.

Spontaneous adenolipoma of the mammary gland in the male F344 rat.

A 110-week-old male F344 rat from the high-dose group of a 104-week carcinogenicity study, exhibited a spontaneously occurring subcutaneous mass in the left axilla extending to the chest. Histologically, the mass was well-demarcated from the adjacent mammary tissue and slightly encapsulated without evidence of infiltration into the surrounding tissues. The mass contained both epithelial and adipose components. The epithelial component consisted of ductal structures of various sizes lined by a single layer of flattened to cuboidal epithelial cells with relatively clear or vacuolated cytoplasm. These ductal structures were well-intermingled with an adipose component that consisted of a uniform monomorphic cell population of mature adipocytes. Both cell types were well-differentiated and did not exhibit cellular atypia. Within the mass, fibrous connective tissue was found in the stroma with infiltration of numerous mast cells. Based on these findings, the mass was diagnosed as an adenolipoma of the mammary gland.

Comparative Genomic Characterization of the Multimammate Mouse Mastomys coucha.

Mastomys are the most widespread African rodent and carriers of various diseases such as the plague or Lassa virus. In addition, mastomys have rapidly gained a large number of mammary glands. Here, we generated a genome, variome, and transcriptomes for Mastomys coucha. As mastomys diverged at similar times from mouse and rat, we demonstrate their utility as a comparative genomic tool for these commonly used animal models. Furthermore, we identified over 500 mastomys accelerated regions, often residing near important mammary developmental genes or within their exons leading to protein sequence changes. Functional characterization of a noncoding mastomys accelerated region, located in the HoxD locus, showed enhancer activity in mouse developing mammary glands. Combined, our results provide genomic resources for mastomys and highlight their potential both as a comparative genomic tool and for the identification of mammary gland number determining factors.

PGC-1α induced browning promotes involution and inhibits lactation in mammary glands.

The PPARγ coactivator 1α (PGC-1α) is a transcriptional regulator of mitochondrial biogenesis and oxidative metabolism. Recent studies have highlighted a fundamental role of PGC-1α in promoting breast cancer progression and metastasis, but the physiological role of this coactivator in the development of mammary glands is still unknown. First, we show that PGC-1α is highly expressed during puberty and involution, but nearly disappeared in pregnancy and lactation. Then, taking advantage of a newly generated transgenic mouse model with a stable and specific overexpression of PGC-1α in mammary glands, we demonstrate that the re-expression of this coactivator during the lactation stage leads to a precocious regression of the mammary glands. Thus, we propose that PGC-1α action is non-essential during pregnancy and lactation, whereas it is indispensable during involution. The rapid preadipocyte-adipocyte transition, together with an increased rate of apoptosis promotes a premature mammary glands involution that cause lactation defects and pup growth retardation. Overall, we provide new insights in the comprehension of female reproductive cycles and lactation deficiency, thus opening new roads for mothers that cannot breastfeed.

Network pharmacology exploration reveals the bioactive compounds and molecular mechanisms of Li-Ru-Kang against hyperplasia of mammary gland.

Li-Ru-Kang (LRK) has been commonly used in the treatment of hyperplasia of mammary gland (HMG) as a cipher prescription and achieved obvious therapeutic effects. However, the bioactive compounds and underlying pharmacological mechanisms remain unclear. This study aims to decipher the bioactive compounds and potential action mechanisms of LRK in the treatment of HMG using an integrated pharmacology approach. The ingredients of LRK and the corresponding drug targets were retrieved through drug target databases and were used to construct the "compound-target-disease" network and function-pathway network. Ultimately, 89 compounds and 2150 drug targets were collected. Gene ontology enrichment analysis revealed that mammary gland alveolus development and mammary gland lobule development were the key biological processes and were regulated simultaneously by three direct targets, including androgen receptor (AR), estrogen receptor (ER) and cyclin-D1. Moreover, 14 compounds of LRK were directly involved in the regulation of the three aforementioned targets. KEGG pathway enrichment analysis found that five signaling pathways and seven direct targets were closely related with HMG treatment by LRK. The results of animal experiments showed that LRK significantly improved the histopathological status of HMG in rats. Additionally, LRK markedly regulated the protein expressions of AR, cyclin-D1, MMP2, MMP3 and MMP9. But interestingly, the effect of LRK on ER was not obvious. This study demonstrated that LRK exerted its therapeutic efficacy based on multi-components, multi-targets and multi-pathways. This research confirms the advantages of network pharmacology analyses and the necessity for experimental verification.