17β-Estradiol and progesterone decrease MDP induced NOD2 expression in bovine mammary epithelial cells

Minthostachys verticillata essential oil modulates cytokine synthesis and Staphylococcus aureus internalization in MAC-T cells at least through TLR4/MyD88/NFkB pathway

The aim of this study was to evaluate the activation pathway(s) triggered by Minthostachys verticillata essential oil (EO) in bovine mammary epithelial cells (MAC-T) challenged with a strain of bovine Staphylococcus aureus. MAC-T cells were stimulated with EO, S. aureus or pre-treated with EO and then challenged with S. aureus. Cytokine's release was measured by ELISA. The mRNA for TLR2, TLR4, NOD2, MyD88 and NFκB was quantified by RT-qPCR. S. aureus adherence and internalization was also evaluated. MAC-T cells stimulated with S. aureus synthesized high levels of IL-1ß and IL-6 were kept up to 48 h, while IL-4 levels were not altered. Cells pre-treated with EO for 2 and 6 h and then challenged with S. aureus showed a significant increase of IL-1β and IL-6. However, in these cells, a decrease in IL-1ß and IL-6 levels and an increase of IL-4 values was observed from 24 h. No significant increase in the expression levels of TLR2 or NOD2 was detected in all stimulated cells. However, the expression of TLR4, MyD88 and NFκB was increased in cells stimulated with S. aureus at 2 and 6 h as well as in cells pre-treated with EO between 2 and 6 h and then challenged with S. aureus. The NFκB expression levels was similar to control at 24 h in all stimulated cells, although pro-inflammatory cytokine levels and TLR4 and MyD88 expression levels remained high in cells stimulated with S. aureus. This results suggested the activation of other pathways independent of MyD88 by the pathogen that involucrated the activation of others transcription factors. Pre-treatment with EO during 2, 6 and 24 h did not affect S. aureus adherence but decreased its internalization. In conclusion, pre-treatment with EO increased the IL-1β and IL-6 synthesis during the first hours post-challenged with S. aureus up-regulating TLR4/MyD88/NFκB pathway. Furthermore, EO increased the IL-4 levels from 6 to 24 h down-regulating the NFκB and possibly other transcription factors activated by the pathogen, which decreased its internalization into MAC-T cells.

Immune defenses of the mammary gland epithelium of dairy ruminants

The epithelium of the mammary gland (MG) fulfills three major functions: nutrition of progeny, transfer of immunity from mother to newborn, and its own defense against infection. The defense function of the epithelium requires the cooperation of mammary epithelial cells (MECs) with intraepithelial leucocytes, macrophages, DCs, and resident lymphocytes. The MG is characterized by the secretion of a large amount of a nutrient liquid in which certain bacteria can proliferate and reach a considerable bacterial load, which has conditioned how the udder reacts against bacterial invasions. This review presents how the mammary epithelium perceives bacteria, and how it responds to the main bacterial genera associated with mastitis. MECs are able to detect the presence of actively multiplying bacteria in the lumen of the gland: they express pattern recognition receptors (PRRs) that recognize microbe-associated molecular patterns (MAMPs) released by the growing bacteria. Interactions with intraepithelial leucocytes fine-tune MECs responses. Following the onset of inflammation, new interactions are established with lymphocytes and neutrophils recruited from the blood. The mammary epithelium also identifies and responds to antigens, which supposes an antigen-presenting capacity. Its responses can be manipulated with drugs, plant extracts, probiotics, and immune modifiers, in order to increase its defense capacities or reduce the damage related to inflammation. Numerous studies have established that the mammary epithelium is a genuine effector of both innate and adaptive immunity. However, knowledge gaps remain and newly available tools offer the prospect of exciting research to unravel and exploit the multiple capacities of this particular epithelium.

Current Understanding and Management of Plasma Cell Mastitis: Can We Benefit from What We Know?

BACKGROUND

Plasma cell mastitis (PCM), also known as mammary duct ectasia, is a chronic nonbacterial breast inflammation characterized by duct expansion and plasma cell infiltration. The severe and intense clinical manifestations profoundly affect the quality of life of female patients. Although the pathological process of PCM is known to include four stages (duct dilatation, inflammation, abscess and fistula), there is still lack of imaging techniques and serum markers with high specificity in clinical practice. Due to recurrent acute attacks and the prolonged healing process of the disease, most patients choose to accept mastectomy.

SUMMARY

We searched for studies, reports and reviews referring to PCM in the past 20 years; more than half of the results were related to animal studies, and little attention has been paid to human beings, which may explain the frequent misdiagnosis of PCM as breast cancer and the limited treatment options. This review focuses on the current diagnostic methods and markers for PCM and hierarchically discusses the typical clinical features, etiological causes and relevant molecular mechanisms of PCM.

KEY MESSAGES

We herein highlight the urgent need to develop more specific and sensitive biomarkers in the clinical laboratory. It will help to establish a standardized flowchart for the diagnosis and treatment of PCM in order to improve recovery for female patients.

Gestational and lactational xenoestrogen exposure disrupts morphology and inflammatory aspects in mammary gland of gerbil mothers during involution

In the mammary gland (MG), the developmental window for gestational/lactational differentiation and growth is highly vulnerable to hormonal disruption. Here we describe that the MG involution process in female gerbil mothers is delayed by bisphenol A (BPA) exposure during gestation and lactation. The process is directly influenced by changes in expression of extracellular matrix proteases MMP-2, MMP-9, and FAP, and the incidence of collagen and elastin is reduced after 7 and 14 days of weaning. A pro-inflammatory environment in the late involution process was confirmed by higher expression of TNF-α, COX-2 and phospho-STAT3 n the MG stroma, allied to increases in the incidence of macrophages and mast cells. These aspects impacted the proliferative pattern of epithelial cells, which decreased on the 14th post-weaning day. These data confirm that the milk production window of susceptibility is vulnerable to the impact of BPA, which promotes a suggestive pro-tumoral microenvironment during mammary involution.

EGF-Induced miR-223 Modulates Goat Mammary Epithelial Cell Apoptosis and Inflammation via ISG15

The health of mammary gland is essential for lactation. Epidermal growth factor (EGF) is reported to play an important role in lactation initiation and miR-223 is a conserved microRNA in anti-inflammation. In this study, EGF was found to induce a higher expression of miR-223 in goat mammary epithelial cell (gMEC). The downstream genes of miR-223 were screened by RNA sequencing, including Interferon-stimulated gene product 15 (ISG15), a pivotal immune responder, which was detected to be downregulated by EGF and miR-223. Due to the correlation between inflammation and apoptosis, the gMEC apoptosis modulated by EGF, miR-223, and ISG15 was investigated, and the protein expressions of Bcl-2/Bax, Caspase 3 and p53 were examined to evaluate the apoptosis of gMEC. The protein expressions of p-STAT3/STAT3, PR, FOXC1, and HOXA10, which had been shown to be related to inflammation, were detected to assess the inflammation of gMEC. This study provided a regulation axis, EGF/miR-223/ISG15, and illustrated its regulation to gMEC apoptosis and inflammation.

LPS-induced SOCS3 antagonizes the JAK2-STAT5 pathway and inhibits β-casein synthesis in bovine mammary epithelial cells

Bovine mammary epithelial cells (BMECs) are essential for lactation in the dairy cow mammary gland, and are often used as a cellular model to study changes in inflammatory responses and lactation functions with exogenous stimuli. Prolactin (PRL) promotes milk protein synthesis by continuously activating the Janus kinase 2 and signal transducer and activator of transcription 5 (JAK2-STAT5) pathway. Lipopolysaccharides (LPS) activates inflammatory responses in cells and inhibits casein synthesis, but the exact mechanism is still unclear. Suppressor of cytokine signaling-3 (SOCS3) is a negative regulator of the JAK-STATs signaling pathway, and regulates a variety of inflammatory responses by inhibiting STAT3. Previous studies also suggested that SOCS3 plays a role in the development and involution of bovine mammary glands. The purpose of this study was to investigate whether LPS activated SOCS3, and whether SOCS3 resisted the regulation of casein synthesis by PRL in a JAK2-STAT5-dependent manner. We treated in vitro BMECs with 125 ng/mL PRL, 10 μg/mL LPS, SOCS3 siRNA (silencing), a SOCS3-GFP adenovirus overexpression vector, or combinations, to determine β-casein expression. We demonstrated that PRL up-regulated phospho-JAK2, phsopho-STAT5 and β-casein expression, whereas LPS caused the opposite effects, and activated SOCS3. SOCS3 overexpression interrupted the JAK2-STAT5 pathway in BMECs. With SOCS3 was silenced, LPS could not activate the JAK2-STAT5 pathway, and no inhibition of β-casein expression was observed. In conclusion, we showed that LPS activated SOCS3 in BMECs, antagonized the JAK2-STAT5 pathway via SOCS3 regulation, and ultimately reduced β-casein expression in these cells.

Liver X receptor α participates in LPS-induced reduction of triglyceride synthesis in bovine mammary epithelial cells

Lipopolysaccharides (LPS) could induce milk fat depression via regulating the body and blood fat metabolism. However, it is not completely clear how LPS might regulate triglyceride synthesis in dairy cow mammary epithelial cells (DCMECs). DCMECs were isolated and purified from dairy cow mammary tissue and treated with LPS. The level of triglyceride synthesis, the expression and activity of the liver X receptor α (LXRα), enzymes related to de novo fatty acid synthesis, and the expression of the fatty acid transporters were investigated. We found that LPS decreased the level of triglyceride synthesis via a down-regulation of the transcription, translation, and nuclear translocation level of the LXRα. The results also indicated that the transcription level of the LXRα target genes, sterol regulatory element binding protein 1 (SREBP1), fatty acid synthetase (FAS), acetyl-CoA carboxylase-1 (ACC1), were significantly down-regulated in DCMECs after LPS treatment. Our data may provide new insight into the mechanisms of milk fat depression caused by LPS.

Identification of Gene Modules and Hub Genes Involved in Mastitis Development Using a Systems Biology Approach

Objective

Mastitis is defined as the inflammation of the mammary gland, which impact directly on the production performance and welfare of dairy cattle. Since, mastitis is a multifactorial complex disease and the molecular pathways underlying this disorder have not been clearly understood yet, a system biology approach was used in this study to a better understanding of the molecular mechanisms behind mastitis.

Methods

Publicly available RNA-Seq data containing samples from milk of five infected and five healthy Holstein cows at five time points were retrieved. Gene Co-expression network analysis (WGCNA) approach and functional enrichment analysis were then applied with the aim to find the non-preserved module of genes that their connectivity were altered under infected condition. Hub genes were identified in the non-preserved modules and were subjected to protein-protein interactions (PPI) network construction.

Results

Among the 25 modules identified, eight modules were non-preserved and were also biologically associated with inflammation, immune response and mastitis development. Interestingly most of the hub genes in the eight modules were also densely connected in the PPI network. Of the hub genes, 250 genes were hubs in both co-expression and PPI networks and most of them were reported to play important roles in immune response or inflammatory pathways. The blue module was highly enriched in inflammatory responses and STAT1 was suggested to play an important role in mastitis development by regulating the immune related genes in this module. Moreover, a set of highly connected genes were identified such as BIRC3, PSMA6, FYN, F11R, NFKBIZ, NFKBIA, GRO1, PHB, CD3E, IL16, GSN, SOCS2, HCK, VAV1 and TLR6, which have been established to be critical for mastitis pathogenesis.

Conclusion

This study improved the understanding of the mechanisms underlying bovine mastitis and suggested eight non-preserved modules along with several most important genes with promising potential in etiology of mastitis.

LPS-induced reduction of triglyceride synthesis and secretion in dairy cow mammary epithelial cells via decreased SREBP1 expression and activity

Sterol regulatory element binding protein 1 (SREBP1) has a central regulatory effect on milk fat synthesis. Lipopolysaccharides (LPS) can induce mastitis and cause milk fat depression in cows. SREBP1 is also known to be associated with inflammatory regulation. Thus, in the current study, we hypothesized that LPS-induced milk fat depression in dairy cow mammary epithelial cells (DCMECs) operates via decreased SREBP1 expression and activity. To examine the hypothesis, DCMECs were isolated and purified from dairy cow mammary tissue and treated with LPS (10 µg/ml). LPS treatment of DCMECs suppressed lipid-metabolism-related transcription factor SREBP1 mRNA expression, nuclear translocation and protein expression, leading to reduced triglyceride content. The transcription levels of acetyl-CoA carboxylase-1 and fatty acid synthetase were significantly down-regulated in DCMECs after LPS treatment, suggesting that acetyl-CoA carboxylase-1 and fatty acid synthetase involved in de novo milk fat synthesis was regulated by SREBP1. In summary, these results suggest that LPS induces milk fat depression in dairy cow mammary epithelial cells via decreased expression of SREBP1 in a time-dependent manner.

Exogenous H2 S exerts biphasic effects on porcine mammary epithelial cells proliferation through PI3K/Akt-mTOR signaling pathway

This study aimed to investigate the effects of exogenous H₂ S on the proliferation of porcine mammary gland epithelial cells (PMECs) and explore the underlying mechanisms. We found that exposure of PMECs to NaHS, at concentrations ranging from 10 to 200 µM, stimulated cell proliferation. However, high concentration of NaHS (600 µM) inhibited PMECs proliferation. Accordingly, 10 µM NaHS significantly increased the percentage of cells undergoing DNA replication, elevated the mRNA and/or protein expression of Cyclin A2, Cyclin D1/3, Cyclin E2 and PCNA, and decreased p21 mRNA expression. In contrast, 600 µM NaHS elicited the opposite effects to that of 10 µM NaHS. In addition, PI3 K/Akt and mTOR signaling pathways were activated or inhibited in response to 10 or 600 µM NaHS, respectively. Furthermore, the promotion of PMECs proliferation, the change of proliferative genes expression, and the activation of mTOR signaling pathway induced by 10 µM NaHS were effectively blocked by PI3 K inhibitor Wortmannin. Similarly, inhibition of mTOR with Rapamycin totally abolished the 10 µM NaHS-induced stimulation of PMECs proliferation and alteration of proliferative genes expression, with no influence on PI3 K/Akt signaling pathway. Moreover, constitutive activation of Akt pathway via transfection of Akt-CA completely eliminated the inhibition of PMECs proliferation and mTOR signaling pathway, and the change of proliferative genes expression induced by 600 µM NaHS. In conclusion, our findings provided evidence that exogenous H₂ S supplied by NaHS exerted biphasic effects on PMECs proliferation, with stimulation at lower doses and suppression at high dose, through the intracellular PI3 K/Akt-mTOR signaling pathway.

Surface Modification of Cardiovascular Stent Material 316L SS with Estradiol-Loaded Poly (trimethylene carbonate) Film for Better Biocompatibility

A delay in the endothelialization process represents a bottleneck in the application of a drug-eluting stent (DES) during cardiovascular interventional therapy, which may lead to a high risk of late restenosis. In this study, we used a novel active drug, estradiol, which may contribute to surface endothelialization of a DES, and prepared an estradiol-loaded poly (trimethylene carbonate) film (PTMC-E5) on the surface of the DES material, 316L stainless steel (316L SS), in order to evaluate its function in improving surface endothelialization. All the in vitro and in vivo experiments indicated that the PTMC-E5 film significantly improved surface hemocompatibility and anti-hyperplasia, anti-inflammation and pro-endothelialization properties. This novel drug-delivery system may provide a breakthrough for the surface endothelialization of cardiovascular DES.