Evolution of the mammary gland from the innate immune system?

Residents or Tourists: Is the Lactating Mammary Gland Colonized by Residential Microbiota?

The existence of the human milk microbiome has been widely recognized for almost two decades, with many studies examining its composition and relationship to maternal and infant health. However, the richness and viability of the human milk microbiota is surprisingly low. Given that the lactating mammary gland houses a warm and nutrient-rich environment and is in contact with the external environment, it may be expected that the lactating mammary gland would contain a high biomass microbiome. This discrepancy raises the question of whether the bacteria in milk come from true microbial colonization in the mammary gland ("residents") or are merely the result of constant influx from other bacterial sources ("tourists"). By drawing together data from animal, in vitro, and human studies, this review will examine the question of whether the lactating mammary gland is colonized by a residential microbiome.

Transcriptome analysis reveals immune function-related mRNA expression in donkey mammary glands during four developmental stages

The low susceptibility to mastitis of female donkey (jenny) mammary glands and the strong immune properties of donkey milk are acknowledged, but little is known about the genes involved in mammary gland immunity in jennies. Herein, we used RNA-sequencing and bioinformatics analyses to explore jenny mammary gland transcriptomes and detect potential functional differentially expressed (DE) mRNAs related to immunity during four specific developmental stages: foetal (F), pubertal (P), adult parous nonlactation (N) and lactation (L). A total of 2497, 583 and 1820 DE mRNAs were identified in jenny mammary glands at F vs. P, P vs. N, and N vs. L, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genomes (KEGG) analyses revealed numerous GO terms related to immune function, especially between F and P. Seven significantly enriched profiles were identified, among which 497 and 1261 DE mRNAs were upregulated in profiles 19 and 17. Eleven mRNAs were enriched in over 10 KEGG pathways. β-2-microglobulin (B2M), immunoglobulin heavy constant mu (IGHM), toll like receptor 2 (TLR2), toll like receptor 4 (TLR4) and myeloid differentiation factor 88 (MYD88) were mainly involved in phosphoinositide 3-kinase (PI3K)-Akt signalling, phagosome and nuclear factor kappa-B (NF-kappa B) signalling pathways. The findings provide insight into the molecular features underpinning the low prevalence of intramammary infections (i.e., mastitis) in donkeys.

Evolution, diversification and function of the maternal-infant dyad in mammalian feeding

The evolution of the mother/infant dyad providing a source of nutrition for infants is essential for the origin and subsequent diversification of mammals. Despite the importance of this dyad, research on maternal and infant function is often treated independently. Our goal is to synthesize the work on maternal and infant function, discuss our own studies of suckling, and compare the origins of lactation and suckling with their ensuing diversification. Our central premise is that while extensive work has demonstrated variation across mammals in the maternal aspect of this system, very little has been done to address how this relates to infant function. We start with a discussion of the fundamental anatomy and physiology of both mother and infant. We next discuss the origin of mammary glands and milk, and infant suckling, which is distinct from their subsequent diversification. We then discuss the diversification of maternal and infant function, highlighting the evolutionary diversity present in maternal function (both anatomically and physiologically), before arguing that the diversity of infant function is unexplored, and needs to be better studied in the future. We end by discussing some of the holes in our understanding, and suggestions for future work that can address these lacunae. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'.

Breastmilk from COVID-19 negative lactating mothers shows neutralizing activity against SARS-COV-2

Breastmilk protects newborns from infections through specific and nonspecific compounds. This study investigated the neutralizing activity against SARS-CoV-2 of breastmilk from SARS-CoV-2 negative, unvaccinated mothers, and compared it to that from infected nursing mothers. We enrolled women after COVID-19 swab testing results upon maternity admission, and divided them into two groups: group A, COVID-19-positive mothers, and group B, negative mothers. Breastmilk was randomly sampled at 2, 7, and 20 days postpartum. We collected 19 samples for Group A and 41 for Group B. A microneutralization assay was used to determine the 50% neutralization (NT50) titre. The presence of neutralizing antibodies was also determined. Group A had 100% neutralizing samples at 2 days postpartum (T0), declining 7 days postpartum (T1) and 20 days postpartum (T2). Group B samples exhibited neutralizing activity mostly at 7 days postpartum (T1) (90%). Negative mothers' samples showed no correlation between NT50 titres and antibodies' presence, suggesting that non-specific breastmilk components may exert antiviral action against SARS-CoV-2.

Immune defences of the mammary gland in dairy ruminants

The mammary gland (MG) of ruminants is essential for assuring the immune protection and nutrition of the suckling youngs. The domestication of these species aimed at increasing milk production for human consumption enhanced udder susceptibility to infections and in this context, a better understanding of the MG immune defences has become a cornerstone for the success of dairy farming. In this review, we explore constitutive and inducible immune mechanisms of the mammary gland and briefly discuss the knowledge gaps that remain to be elucidated for the implementation of strategies focused on boosting mammary immune responses.

Genetic polymorphisms in immune- and inflammation-associated genes and their association with bovine mastitis resistance/susceptibility

Bovine mastitis, the inflammation of the mammary gland, is a contagious disease characterized by chemical and physical changes in milk and pathological changes in udder tissues. Depressed immunity and higher expression of inflammatory cytokines with an elevated milk somatic cell count can be observed during mastitis in dairy cattle. The use of somatic cell count (SCC) and somatic cell score (SCS) as correlated traits in the indirect selection of animals against mastitis resistance is in progress globally. Traditional breeding for mastitis resistance seems difficult because of the low heritability (0.10-0.16) of SCC/SCS and clinical mastitis. Thus, genetic-marker-selective breeding to improve host genetics has attracted considerable attention worldwide. Moreover, genomic selection has been found to be an effective and fast method of screening for dairy cattle that are genetically resistant and susceptible to mastitis at a very early age. The current review discusses and summarizes the candidate gene approach using polymorphisms in immune- and inflammation-linked genes (CD4, CD14, CD46, TRAPPC9, JAK2, Tf, Lf, TLRs, CXCL8, CXCR1, CXCR2, C4A, C5, MASP2, MBL1, MBL2, LBP, NCF1, NCF4, MASP2, A2M, and CLU, etc.) and their related signaling pathways (Staphylococcus aureus infection signaling, Toll-like receptor signaling, NF-kappa B signaling pathway, Cytokine-cytokine receptor, and Complement and coagulation cascades, etc.) associated with mastitis resistance and susceptibility phenotypic traits (IL-6, interferon-gamma (IFN-γ), IL17, IL8, SCS, and SCC) in dairy cattle.

Immunomodulatory Effects of Bacterial Toll-like Receptor Ligands on the Phenotype and Function of Milk Immune Cells in Dromedary Camel

(1) Toll-like receptors (TLR) are a family of pattern recognition receptors that sense distinct molecular patterns of microbial origin. Although the immune cell composition of camel milk has been recently described, host-pathogen interaction studies in the camel mammary gland are still scarce. The present study aimed to use a whole milk stimulation assay for investigating the modulatory effect of selected Toll-like receptor (TLR) ligands on the phenotype and function of milk immune cells. (2) Methods-camel milk samples (n = 7) were stimulated in vitro with the TLR4 ligand LPS or the TLR2/1 ligand Pam3CSK4, and separated milk cells were evaluated for stimulation-induced shape change, the expression of cell surface markers, phagocytosis, apoptosis, ROS production, and NETosis. Stimulation with PMA was used as a control stimulation. (3) Results-all stimulants induced shape change in milk cells, change in the expression of several cell markers, and increased cell apoptosis and NETosis. In addition, stimulation with Pam3CSK4 and PMA was associated with enhanced ROS production, while only PMA stimulation resulted in enhanced bacterial phagocytosis by milk immune cells. (4) Conclusions-our data indicates selective modulating effects of the TLR ligands LPS and Pam3CSK4 on camel milk phagocytes. These results may have implications for the use of synthetic TLR agonists as immunomodulatory adjuvants of the immune response to intra-mammary vaccines against mastitis pathogens.

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.

Maternal Vitamin D Status Correlates to Leukocyte Antigenic Responses in Breastfeeding Infants

It is unknown if vitamin D (vitD) sufficiency in breastfeeding mothers can lead to physiological outcomes for their children that are discernible from infant vitD sufficiency per se. In a 3-month, randomized vitD supplementation study of mothers and their exclusively breastfeeding infants, the effects of maternal vitD sufficiency were determined on infant plasma concentrations of 25-hydroxyvitamin D (i.e., vitD status) and 11 cytokines. An inverse correlation was seen between maternal vitD status and infant plasma TNF concentration (r = −0.27; p < 0.05). Infant whole blood was also subjected to in vitro antigenic stimulation. TNF, IFNγ, IL-4, IL-13, and TGFβ1 responses by infant leukocytes were significantly higher if mothers were vitD sufficient but were not as closely correlated to infants’ own vitD status. Conversely, IL-10 and IL-12 responses after antigenic challenge were more correlated to infant vitD status. These data are consistent with vitD-mediated changes in breast milk composition providing immunological signaling to breastfeeding infants and indicate differential physiological effects of direct-infant versus maternal vitD supplementation. Thus, consistent with many previous studies that focused on the importance of vitD sufficiency during pregnancy, maintenance of maternal sufficiency likely continues to affect the health of breastfed infants.

Mammalian tumor-like organs. 1. The role of tumor-like normal organs and atypical tumor organs in the evolution of development (carcino-evo-devo)

Background

Earlier I hypothesized that hereditary tumors might participate in the evolution of multicellular organisms. I formulated the hypothesis of evolution by tumor neofunctionalization, which suggested that the evolutionary role of hereditary tumors might consist in supplying evolving multicellular organisms with extra cell masses for the expression of evolutionarily novel genes and the origin of new cell types, tissues, and organs. A new theory—the carcino-evo-devo theory—has been developed based on this hypothesis.

Main text

My lab has confirmed several non-trivial predictions of this theory. Another non-trivial prediction is that evolutionarily new organs if they originated from hereditary tumors or tumor-like structures, should recapitulate some tumor features in their development. This paper reviews the tumor-like features of evolutionarily novel organs. It turns out that evolutionarily new organs such as the eutherian placenta, mammary gland, prostate, the infantile human brain, and hoods of goldfishes indeed have many features of tumors. I suggested calling normal organs, which have many tumor features, the tumor-like organs.

Conclusion

Tumor-like organs might originate from hereditary atypical tumor organs and represent the part of carcino-evo-devo relationships, i.e., coevolution of normal and neoplastic development. During subsequent evolution, tumor-like organs may lose the features of tumors and the high incidence of cancer and become normal organs without (or with almost no) tumor features.

Human Milk, More Than Simple Nourishment

Human breast milk not only has nutritional properties but also holds a functional role. It contains various bioactive factors (lactoferrin, lysozyme, leukocytes, immunoglobulins, cytokines, hormones, human milk oligosaccharides, microbiome, microRNAs and stem cells) shown to contribute to several short- and long-term health outcomes. Some of these factors appear to be involved in the infant's neuro-cognitive development, anti-oncogenic processes, cellular communication and differentiation. Furthermore, breast milk is increasingly recognized to have dynamic characteristics and to play a fundamental role in the cross-talking mother-neonate. This narrative review aims to provide a summary and an update on these bioactive substances, exploring their functions mainly on immunomodulation, microbiome and virome development. Although the knowledge about breast milk potentiality has significantly improved, leading to discovering unexpected functions, the exact mechanisms with which breast milk exercises its bioactivity have not been completely clarified. This can represent a fertile ground for exploring and understanding the complexity behind these functional elements to develop new therapeutic strategies.

The molecular basis of mammary gland development and epithelial differentiation

Our understanding of the molecular events underpinning the development of mammalian organ systems has been increasing rapidly in recent years. With the advent of new and improved next-generation sequencing methods, we are now able to dig deeper than ever before into the genomic and epigenomic events that play critical roles in determining the fates of stem and progenitor cells during the development of an embryo into an adult. In this review, we detail and discuss the genes and pathways that are involved in mammary gland development, from embryogenesis, through maturation into an adult gland, to the role of pregnancy signals in directing the terminal maturation of the mammary gland into a milk producing organ that can nurture the offspring. We also provide an overview of the latest research in the single-cell genomics of mammary gland development, which may help us to understand the lineage commitment of mammary stem cells (MaSCs) into luminal or basal epithelial cells that constitute the mammary gland. Finally, we summarize the use of 3D organoid cultures as a model system to study the molecular events during mammary gland development. Our increased investigation of the molecular requirements for normal mammary gland development will advance the discovery of targets to predict breast cancer risk and the development of new breast cancer therapies.

The effects of probiotic supplementation on the gene expressions of immune cell surface markers and levels of antibodies and pro-inflammatory cytokines in human milk

OBJECTIVE

This study investigated the impact of probiotic supplementation on the gene expressions of cluster of differentiation (CD) as cell markers and the concentrations of antibodies and cytokines in human milk.

STUDY DESIGN

Gene expressions of CD28, CD19, and CD38 were determined in milk from 15 women ingesting daily probiotics (from Greek yogurt) and 12 women who do not consume probiotics. Concentrations of antibodies and cytokines were measured using ELISA.

RESULTS

Gene expression of CD28 tended to be higher in milk from mothers ingesting daily probiotics than mothers who did not take probiotics. Interleukin-6 (IL-6) concentration in milk was higher in mothers ingesting probiotics than those who do not consume probiotics. The increase of IL-6 level in human milk was positively correlated with total IgA and IgG concentrations.

CONCLUSIONS

Probiotic supplementation could enhance the secretion of IL-6 in human milk. Human milk IL-6 may improve neonatal immunity due to its stimulation of total IgA and IgG.

The Antiviral Properties of Human Milk: A Multitude of Defence Tools from Mother Nature

The anti-infective properties of breast milk have been known for decades. In recent years, an increasing number of papers have described the variety of bioactive compounds that are present in breast milk with varying degrees of antiviral activity. However, to date, the totality of the properties of these compounds is not fully understood and, above all, their synergistic interaction is not yet known. The purpose of this review is to describe the current knowledge about the antiviral compounds in breast milk, both with specific and non-specific action against pathogens. Due to the current pandemic situation from SARS-CoV-2 (Severe acute respiratory syndrome Coronavirus-2), research has focused on a multitude of potential antiviral substances, taking breast milk as a biological model of reference. Future research is needed to expand the knowledge of these compounds, which will hopefully assist in the development of therapies applicable even at later ages.

Marsupial milk: a fluid source of nutrition and immune factors for the developing pouch young

Marsupials have a very different reproductive strategy to eutherians. An Australian marsupial, the tammar wallaby (Macropus eugenii) has a very short pregnancy of about 26.5 days, with a comparatively long lactation of 300-350 days. The tammar mother gives birth to an altricial, approximately 400 mg young that spends the first 200 days postpartum (p.p.) in its mother's pouch, permanently (0-100 days p.p.; Phase 2A) and then intermittently (100-200 days p.p.; Phase 2B) attached to the teat. The beginning of Phase 3 marks the first exit from the pouch (akin to the birth of a precocious eutherian neonate) and the supplementation of milk with herbage. The marsupial mother progressively alters milk composition (proteins, fats and carbohydrates) and individual milk constituents throughout the lactation cycle to provide nutrients and immunological factors that are appropriate for the considerable physiological development and growth of her pouch young. This review explores the changes in tammar milk components that occur during the lactation cycle in conjunction with the development of the young.

Structural Biology of Calcium Phosphate Nanoclusters Sequestered by Phosphoproteins

Biofluids that contain stable calcium phosphate nanoclusters sequestered by phosphopeptides make it possible for soft and hard tissues to co-exist in the same organism with relative ease. The stability diagram of a solution of nanocluster complexes shows how the minimum concentration of phosphopeptide needed for stability increases with pH. In the stable region, amorphous calcium phosphate cannot precipitate. Nevertheless, if the solution is brought into contact with hydroxyapatite, the crystalline phase will grow at the expense of the nanocluster complexes. The physico-chemical principles governing the formation, composition, size, structure, and stability of the complexes are described. Examples are given of complexes formed by casein, osteopontin, and recombinant phosphopeptides. Application of these principles and properties to blood serum, milk, urine, and resting saliva is described to show that under physiological conditions they are in the stable region of their stability diagram and so cannot cause soft tissue calcification. Stimulated saliva, however, is in the metastable region, consistent with its role in tooth remineralization. Destabilization of biofluids, with consequential ill-effects, can occur when there is a failure of homeostasis, such as an increase in pH without a balancing increase in the concentration of sequestering phosphopeptides.

TDP-43 facilitates milk lipid secretion by post-transcriptional regulation of Btn1a1 and Xdh

Milk lipid secretion is a critical process for the delivery of nutrition and energy from parent to offspring. However, the underlying molecular mechanism is less clear. Here we report that TDP-43, a RNA-binding protein, underwent positive selection in the mammalian lineage. Furthermore, TDP-43 gene (Tardbp) loss induces accumulation of large lipid droplets and severe lipid secretion deficiency in mammary epithelial cells to outside alveolar lumens, eventually resulting in lactation failure and pup starvation within three weeks postpartum. In human milk samples from lactating women, the expression levels of TDP-43 is positively correlated with higher milk output. Mechanistically, TDP-43 exerts post-transcriptional regulation of Btn1a1 and Xdh mRNA stability, which are required for the secretion of lipid droplets from epithelial cells to the lumen. Taken together, our results highlights the critical role of TDP-43 in milk lipid secretion, providing a potential strategy for the screening and intervention of clinical lactation insufficiency.

Milk lipid secretion is a critical process for the delivery of nutrition and energy from parent to offspring. Here the authors found that TDP-43, a RNA-binding protein, is required for milk lipid secretion by post-transcriptional regulation of Btn1a1 and Xdh mRNA stability.

Impact of Holder pasteurization on immunological properties of human breast milk over the first year of lactation

BACKGROUND

The timing of milk donations to human milk banks ranges from a few days to more than 1 year after delivery, and the Holder method is used for pasteurization. We evaluated the effect of temporal variation and thermal treatment on the immunological properties of milk.

METHODS

We analyzed 73 milk samples, raw and after pasteurization, donated at different lactation stages. We studied antibodies, lysozyme, cytokines, soluble receptors, and factors with impact on barrier function. We also evaluated in vitro the capacity of milk to modulate nuclear factor-κB (NF-κB) signaling in an HT-29 epithelial cell line stimulated with tumor necrosis factor-α (TNF-α).

RESULTS

With few exceptions, immune components exhibited their highest levels in colostrum, and were stable in the various stages of mature milk. Pasteurization altered the immunological composition of milk, and very drastically for some components. Raw milk of the first year reduced NF-κB activation in HT-29 cells treated with TNF-α to approximately the same extent, and Holder pasteurization significantly affected this capacity.

CONCLUSIONS

Overall, the present work reports that mature donated milk is equally valuable over the first year of lactation, but warns about drastic losses of anti-inflammatory properties during Holder pasteurization that could be critical for the health of preterm infants.

Formation and degradation of lipid droplets in human adipocytes and the expression of aldehyde oxidase (AOX)

Lipid droplet (LD) binding proteins in mammary glands and in adipocytes were previously compared and striking similar sets of these specific proteins demonstrated. Xanthine oxidoreductase (XOR) together with perilipins and the lactating mammary gland protein butyrophilin play an important role in the secretion process of LDs into milk ducts. In contrast, in adipose tissue and in adipocytes, mainly perilipins have been described. Moreover, XOR was reported in mouse adipose tissue and adipocyte culture cells as “novel regulator of adipogenesis”. This obvious coincidence of protein sets prompted us to revisit the formation of LDs in human-cultured adipocytes in more detail with special emphasis on the possibility of a LD association of XOR. We demonstrate by electron and immunoelectron microscopy new structural details on LD formation in adipocytes. Surprisingly, by immunological and proteomic analysis, we identify in contrast to previous data showing the enzyme XOR, predominantly the expression of aldehyde oxidase (AOX). AOX could be detected tightly linked to LDs when adipocytes were treated with starvation medium. In addition, the majority of cells show an enormous interconnected, tubulated mitochondria network. Here, we discuss that (1) XOR is involved—together with perilipins—in the secretion of LDs in alveolar epithelial cells of the lactating mammary gland and is important in the transcytosis pathway of capillary endothelial cells. (2) In cells, where LDs are not secreted, XOR cannot be detected at the protein level, whereas in contrast in these cases, AOX is often present. We detect AOX in adipocytes together with perilipins and find evidence that these proteins might direct LDs to mitochondria. Finally, we here report for the first time the exclusive and complementary localization of XOR and AOX in diverse cell types.

Lactoferrin in Human Milk of Prolonged Lactation

Among the immunologically important bioactive factors present in human milk, lactoferrin (Lf) has emerged as a key player with wide-ranging features that directly and indirectly protect the neonate against infection caused by a variety of pathogens. The concentration of Lf in human milk is lactation-stage related; colostrum contains more than 5 g/L, which then significantly decreases to 2–3 g/L in mature milk. The milk of mothers who are breastfeeding for more than one year is of a standard value, containing macronutrients in a composition similar to that of human milk at later stages. The aim of this study was to evaluate lactoferrin concentration in prolonged lactation from the first to the 48th month postpartum. Lactating women (n = 120) up to 48 months postpartum were recruited to the study. The mean value of lactoferrin concentration was the lowest in the group of 1–12 months of lactation (3.39 ± 1.43 g/L), significantly increasing in the 13–18 months group (5.55 ± 4.00 g/L; p < 0.006), and remaining at a comparable level in the groups of 19–24 month and over 24 months (5.02 ± 2.97 and 4.90 ± 3.18 g/L, respectively). The concentration of lactoferrin in mother’s milk also showed a positive correlation with protein concentration over lactation from the first to the 48th month (r = 0.3374; p = 0.0002). Our results demonstrate the high immunology potential of human milk during prolonged lactation and that Lf concentration is close to the Lf concentration in colostrum. Evidence of stable or rising immunoprotein levels during prolonged lactation provides an argument for foregoing weaning; however, breastfeeding must be combined with solid foods meet the new requirements of a rapidly growing six-month or older baby.

The Role of Heritable Tumors in Evolution of Development: a New Theory of Carcino-evo-devo

The hypothesis of evolution by tumor neofunctionalization (the "main hypothesis") describes the possible role of hereditary tumors in evolution. The present article examines the relationship of the main hypothesis to other biological theories. As shown in this paper, the main hypothesis does not contradict to the existing biological theories, but fills the lacunas between them and explains some unexplained (or not completely understood) questions. Common features of embryonic development and tumorigenesis are described by several recognized theories. Similarities between normal development and tumorigenesis suggest that tumors could participate in the evolution of ontogenesis and in the origin of new cell types, tissues and organs. A wide spectrum of non-trivial explanations and non-trivial predictions in different fields of biology, suggested by the main hypothesis, is an indication of its fundamental nature and the potential to become a new biological theory, a theory of the role of tumors in evolution of development, or carcino-evo-devo.

Relationship Between mRNA of Immune Factors Expressed by Milk Somatic Cells and Bacteria Present in Healthy Lactating Holstein Cows

Introduction

The characteristics of immune factors in somatic cells from lactating dairy cows and their association with commensal bacteria in normal milk have not been clarified. This study investigated the relationship between the pathogenic bacteria in milk and somatic cell immune factors in healthy lactating cows.

Material and Methods

In total 44 healthy Holstein cows were studied on one farm. Milk samples were collected aseptically using a cannula and these samples were cultured for detection of bacteria and analysis of mRNA of immune factors expressed by somatic cells. Cows were divided into two groups based on the microbial status of their milk samples: 12 cows showed bacteria in cultures (positive group), and the other 32 cows did not (negative group).

Results

The mRNA levels of IL-6, lactotransferrin, and cathelicidin expressed by somatic cells after milking decreased significantly compared to those before milking in both groups (P < 0.05). There were significantly lower mRNA levels of IL-6 and cathelicidin in the positive group compared to those in the negative group before milking.

Conclusion

These results suggest that mRNA levels of IL-6 and cathelicidin expressed by the somatic cells may be affected by the presence of bacteria in healthy lactating dairy cows.

Host Microbe Interactions in the Lactating Mammary Gland

The bacteria present in human milk constitute the human milk microbiome (hMM). Both the older culture-based work and the more recent studies using molecular detection of bacterial DNA have reached similar conclusions: the hMM mostly consists of commensal staphylococci such as Staphylococcus epidermidis, and streptococci. The prevalence of other bacterial groups such lactobacilli varies widely, while the abundance and prevalence of bifidobacteria is generally low. Recently, the hMM became accepted as a part of a physiologically normal state with suggested potential health benefits. Most research on the hMM has focused on its composition and potential effect on the breastfed infant. A major role as a microbiome inoculum for the infant gut has been proposed, but remains to be clearly demonstrated. Herein, we also discuss the emerging connection between the hMM and mammary gland physiology and lactation. Similarities between the mammary gland and mucosal interfaces are considerable, and in particular mucosal-like immune attributes of mammary gland. The potential role of hMM-host interactions in the mammary gland in maternal health is explored with a primary focus on lactational mastitis.

Prolonged milk provisioning and extended maternal care in the milking spider Toxeus magnus: biological implications and questions unresolved

Prolonged milk provisioning and extended parental care for nutritionally independent offspring, previously considered to only co-occur in long-lived mammals (Clutton-Brock, 1991; Royle et al., 2012), were recently reported in the reproduction of the milking spider, Toxeus magnus (Chen et al. 2018). Newly hatched T. magnus spiderlings require 53 days to develop to maturity, with an average adult body length of 6.6 mm. The mother provides milk droplets to her newly hatched spiderlings until they develop into subadults (~38 days old), during which their body lengths increase from 0.9 mm at birth to 5.3 mm at weaning. Although spiderlings can forage for themselves at around 20 days old, they remain in the breeding nest for weeks after maturity.

In utero exposure to commercial artificial sweeteners affects mice development and mammary gland structure

Commercial artificial sweeteners present in the market are usually made of combination of nutritive and artificial sweeteners such as sorbitol and aspartame. The aim of this research was to study the effect of in utero exposure to commercial artificial sweeteners on the mouse development and on mammary gland in different stages (18-day embryos and 4-week-old mice). Pregnant mice of treated groups were given 50 mg/kg body weight of commercial artificial sweetener. The dose was given on day 1 of pregnancy until 3-week nursing, while the controls were given distilled water. Congenital malformations were seen in treated 18-day fetus and 4-week-old mice, such as a significant decrease in the diameter of the placenta and the weight of the fetuses, while in 4-week-old mice, a significant decrease in the length of the body, limbs, and tail was seen compared to the controls. The result of this study showed that in 18-day fetuses, clusters of mammary gland in the treated mice seemed to be more differentiated than the controls. In 4-week-old mice, the number of mammary gland ducts in the treated group was significantly more than the control group, and the lumen of the ducts in the treated sections seemed to be narrower than the controls, also many regressing terminal end buds (TEBs) were seen in the treated group. A significant increase in the mammary gland area of treated group was seen compared to the controls.

Immune components of early breastmilk: Association with maternal factors and with reported food allergy in childhood

BACKGROUND

Breastmilk (BM) may participate in driving gut barrier function and immunity in the neonate. We analyzed immune and growth factor concentrations in early BM and their association with maternal/environmental characteristics and with food allergy (FA) in childhood.

METHODS

One BM sample was collected in maternity from some mothers in the EDEN birth cohort (n = 2002 mother-child dyads). A random selection was performed among available samples (subcohort, n = 272), for which all deliveries were full-term, various maternal/environmental characteristics were recorded, and parents answered yearly the question "Has a medical doctor diagnosed a FA in your child?" (26 parent-reported FA cases). Only samples collected between day 2 and day 6 post-partum were considered for descriptive analysis (n = 263). Samples for all other FA cases available were added to the subcohort (46 additional cases; "casecohort" design). Fifty cytokines, antibodies, and growth factor concentrations were determined using multiplexed kits and analyzed using robust statistical procedures.

RESULTS

BM components exhibited wide concentration ranges and global day-to-day variation. Different clusters of correlated factors appeared, with components from the main cluster related to maternal diet during pregnancy. Primiparity was positively associated with eleven other components, whereas other factors (eg, maternal atopy and smoking) were related to fewer components. Finally, the casecohort design highlighted a positive association between CXCL10, TNFβ, and IL-2 concentrations and reported FA in childhood.

CONCLUSION

Beyond the unique description of early BM composition, we show that immune information transmitted to the neonate is related to various maternal factors and identified components associated with FA diagnosis in childhood.

Immune cell counts and signaling in body fluids of cows vaccinated against Clostridium difficile

BACKGROUND

New treatment options are needed to prevent relapses following failed antibiotic therapies of Clostridium difficile infections (CDI) in humans. The concomitant therapy with an anti-C. difficile IgA containing whey protein concentrate can support the sustainable recovery of CDI patients. For 31 weeks, nine dairy cows were continuously vaccinated with several anti-C. difficile vaccines by certain routes of administration to produce anti-C. difficile IgA enriched milk. The study aimed at finding decisive differences between low responder (LR) and high responder (HR) cows (> 8.0 µg ml-1 total milk C. difficile specific IgA) concerning their immune response to vaccination on cellular and molecular biological levels.

RESULTS

The results of total and differential cell counting (DCC) in blood and milk and the outcomes of the gene expression analysis of selected immune factors were assessed relating to the usage of two vaccine batches for injection (MucoCD-I batch A and B), marking two immunization (IM) periods, and compared to a control group (Ctr). The MucoCD-I batch A caused short-term leukopenia followed by leukocytosis in the blood of LR and HR. The total somatic cell counts in milk were not altered by the treatment. The DCC revealed that the leukocytes of the treated groups were partly impaired by the treatment. The gene expression analysis exposed cumulative and sustainable differences (p < 0.05) between LR and HR for the genes encoding for lactoferrin, CXCL8, IL1β, IL2, IL6, IL12β, IFNγ, CD4 and CD163. The regulation of the epithelial IgA cell receptor PIGR was not impaired by the IM. In contrast to the vaccination with MucoCD-I batch A, the second IM period with MucoCD-I batch B resulted in mitigation and synchronization of the treated groups' immune responses.

CONCLUSIONS

The inversely regulated cytokines in the blood and milk cells of the treated groups led to a variously directed, local T cell response resulting in their different production intensities of C. difficile specific IgA in milk.

Development of immune and microbial environments is independently regulated in the mammary gland

Breastfeeding is important for mammals, providing immunological and microbiological advantages to neonates, together with the nutritional supply from the mother. However, the mechanisms of this functional diversity in the mammary gland remain poorly characterized. Here, we show that, similar to the gastrointestinal tract, the mammary gland develops immune and microbial environments consisting of immunoglobulin A (IgA) and the microflora, respectively, both of which are important for protecting neonates and the mother from infectious diseases. The IgA production and microflora development are coordinated in the gastrointestinal tract but seem to be independently regulated in the mammary gland. In particular, the chemokine (C-C motif) ligand 28 and poly-Ig receptor, crucial molecules for the IgA production in milk, were expressed normally in germ-free lactating mice but were almost undetectable in postweaning mothers, regardless of the microflora presence. Our findings offer insights into potentially improving the quality of breastfeeding, using both immunological and microbiological approaches.

CYP1A1 Relieves Lipopolysaccharide-Induced Inflammatory Responses in Bovine Mammary Epithelial Cells

The expression of cytochrome P4501A1 (CYP1A1) enzyme is changed in various organs during the host response to inflammation or infection, leading to alterations in the metabolism of endogenous and exogenous compounds. Results of this study showed that CYP1A1 expression was significantly downregulated in the mammary tissue of bovine with mastitis, in inflammatory epithelial cells (INEs) extracted from the tissue, and in lipopolysaccharide- (LPS-) induced INEs compared with their corresponding counterparts. Overexpression of CYP1A1 in bovine mammary epithelial cells alleviated the LPS-induced inhibition of epithelial proliferation, abated the LPS-induced increase of gene expression and protein secretion of inflammatory cytokine tumor necrosis factor-α and interleukin-6, and attenuated the LPS-induced activation of NF-κB signaling. These findings suggest that CYP1A1 has immense potential in the regulation of inflammatory responses in bovine mammary epithelial cells during mastitis and may serve as a useful therapeutic target in mitigating injuries caused by inflammatory overreaction.

An effort toward molecular neuroeconomics of food deprivation induced food hoarding in mice: focus on xanthine oxidoreductase gene expression and xanthine oxidase activity

The crucial role of xanthine oxidoreductase (XOR) gene and its active isoform, xanthine oxidase (XO), in purine metabolism and cellular oxidative status led us to investigative their fluctuations in food deprivation induced food hoarding in mice. After, 10 h food deprivation, mice that hoarded lesser than 5 g were considered as 'low-hoarders' while mice that hoarded higher than 20 g were considered as 'high-hoarders'. Mice who hoarded between 5 to 20 g of food were excluded from study. An increase (1.133-fold) in encephalic XOR expression has been found in high-hoarders compared with low-hoarders without sex consideration. An increase (~ 50-fold) in encephalic XOR in female high-hoarders vs. female low-hoarders while a decrease (0.026-fold) in encephalic XOR in male high-hoarders vs. male low-hoarders demonstrated that food deprivation is associated with sex-dependent alteration in XOR expression. The encephalic and hepatic XO activities were not different in male high-hoarders vs. male low-hoarders while encephalic XO activity has been also increased significantly in female high-hoarders (~ 4 times) compared to female low-hoarders. The plasma and hepatic XO activities tended to be increased in female high-hoarders as compared to female low-hoarders, however the uric acid levels in plasma, liver and brain tissues were not altered in female high-hoarders as compared to female low-hoarders. In sum, this study generally proposed that different gene expression space is behind of hoarding behavior in a food-deprived mouse model. Specifically, this is the first study that examined the levels of encephalic XO activity and XOR expression in hoarding behavior, although additional studies are requested.

IgA Function in Relation to the Intestinal Microbiota

IgA is the dominant immunoglobulin isotype produced in mammals, largely secreted across the intestinal mucosal surface. Although induction of IgA has been a hallmark feature of microbiota colonization following colonization in germ-free animals, until recently appreciation of the function of IgA in host-microbial mutualism has depended mainly on indirect evidence of alterations in microbiota composition or penetration of microbes in the absence of somatic mutations in IgA (or compensatory IgM). Highly parallel sequencing techniques that enable high-resolution analysis of either microbial consortia or IgA sequence diversity are now giving us new perspectives on selective targeting of microbial taxa and the trajectory of IgA diversification according to induction mechanisms, between different individuals and over time. The prospects are to link the range of diversified IgA clonotypes to specific antigenic functions in modulating the microbiota composition, position and metabolism to ensure host mutualism.

TRIENNIAL LACTATION SYMPOSIUM/BOLFA:Historical perspectives of lactation biology in the late 20th and early 21st centuries

The latter half of the 20th century and the early portion of the 21st century will be recognized as the "Golden Age" of lactation biology. This period corresponded with the rise of systemic, metabolomic, molecular, and genomic biology. It includes the discovery of the structure of DNA and ends with the sequencing of the complete genomes of humans and all major domestic animal species including the dairy cow. This included the ability to identify polymorphisms in the nucleic acid sequence, which can be tied to specific differences in cellular, tissue, and animal performance. Before this period, classical work using endocrine ablation and replacement studies identified the mammary gland as an endocrine-dependent organ. In the early 1960s, the development of RIA and radioreceptor assays permitted the study of the relationship between endocrine patterns and mammary function. The ability to measure nucleic acid content of tissues opened the door to study of the factors regulating mammary growth. The development of high-speed centrifugation in the 1960s allowed separation of specific cell organelles and their membranes. The development of transmission and scanning electron microscopy permitted the study of the relationship between structure and function in the mammary secretory cell. The availability of radiolabeled metabolites provided the opportunity to investigate the metabolic pathways and their regulation. The development of concepts regarding the coordination of metabolism to support lactation integrated our understanding of nutrient partitioning and homeostasis. The ability to produce recombinant molecules and organisms permitted enhancement of lactation in farm animal species and the production of milk containing proteins of value to human medicine. These discoveries and others contributed to vastly increased dairy farm productivity in the United States and worldwide. This review will include the discussion of the centers of excellence and scientists who labored in these fields to produce the harvest of knowledge we enjoy today.

Breastfeeding Behaviors and the Innate Immune System of Human Milk: Working Together to Protect Infants against Inflammation, HIV-1, and Other Infections

The majority of infants’ breastfeeding from their HIV-infected mothers do not acquire HIV-1 infection despite exposure to cell-free virus and cell-associated virus in HIV-infected breast milk. Paradoxically, exclusive breastfeeding regardless of the HIV status of the mother has led to a significant decrease in mother-to-child transmission (MTCT) compared with non-exclusive breastfeeding. Although it remains unclear how these HIV-exposed infants remain uninfected despite repeated and prolonged exposure to HIV-1, the low rate of transmission is suggestive of a multitude of protective, short-lived bioactive innate immune factors in breast milk. Indeed, recent studies of soluble factors in breast milk shed new light on mechanisms of neonatal HIV-1 protection. This review highlights the role and significance of innate immune factors in HIV-1 susceptibility and infection. Prevention of MTCT of HIV-1 is likely due to multiple factors, including innate immune factors such as lactoferrin and elafin among many others. In pursuing this field, our lab was the first to show that soluble toll-like receptor 2 (sTLR2) directly inhibits HIV infection, integration, and inflammation. More recently, we demonstrated that sTLR2 directly binds to selective HIV-1 proteins, including p17, gp41, and p24, leading to significantly reduced NFκB activation, interleukin-8 production, CCR5 expression, and HIV infection in a dose-dependent manner. Thus, a clearer understanding of soluble milk-derived innate factors with known antiviral functions may provide new therapeutic insights to reduce vertical HIV-1 transmission and will have important implications for protection against HIV-1 infection at other mucosal sites. Furthermore, innate bioactive factors identified in human milk may serve not only in protecting infants against infections and inflammation but also the elderly; thus, opening the door for novel innate immune therapeutics to protect newborns, infants, adults, and the elderly.

Rapid changes in Atlantic grey seal milk from birth to weaning - immune factors and indicators of metabolic strain

True seals have the shortest lactation periods of any group of placental mammal. Most are capital breeders that undergo short, intense lactations, during which they fast while transferring substantial proportions of their body reserves to their pups, which they then abruptly wean. Milk was collected from Atlantic grey seals (Halichoerus grypus) periodically from birth until near weaning. Milk protein profiles matured within 24 hours or less, indicating the most rapid transition from colostrum to mature phase lactation yet observed. There was an unexpected persistence of immunoglobulin G almost until weaning, potentially indicating prolonged trans-intestinal transfer of IgG. Among components of innate immune protection were found fucosyllactose and siallylactose that are thought to impede colonisation by pathogens and encourage an appropriate milk-digestive and protective gut microbiome. These oligosaccharides decreased from early lactation to almost undetectable levels by weaning. Taurine levels were initially high, then fell, possibly indicative of taurine dependency in seals, and progressive depletion of maternal reserves. Metabolites that signal changes in the mother’s metabolism of fats, such as nicotinamide and derivatives, rose from virtual absence, and acetylcarnitines fell. It is therefore possible that indicators of maternal metabolic strain exist that signal the imminence of weaning.

Wound healing, calcium signaling, and other novel pathways are associated with the formation of butterfly eyespots

Background

One hypothesis surrounding the origin of novel traits is that they originate from the co-option of pre-existing genes or larger gene regulatory networks into novel developmental contexts. Insights into a trait’s evolutionary origins can, thus, be gained via identification of the genes underlying trait development, and exploring whether those genes also function in other developmental contexts. Here we investigate the set of genes associated with the development of eyespot color patterns, a trait that originated once within the Nymphalid family of butterflies. Although several genes associated with eyespot development have been identified, the eyespot gene regulatory network remains largely unknown.

Results

In this study, next-generation sequencing and transcriptome analyses were used to identify a large set of genes associated with eyespot development of Bicyclus anynana butterflies, at 3-6 h after pupation, prior to the differentiation of the color rings. Eyespot-associated genes were identified by comparing the transcriptomes of homologous micro-dissected wing tissues that either develop or do not develop eyespots in wild-type and a mutant line of butterflies, Spotty, with extra eyespots. Overall, 186 genes were significantly up and down-regulated in wing tissues that develop eyespots compared to wing tissues that do not. Many of the differentially expressed genes have yet to be annotated. New signaling pathways, including the Toll, Fibroblast Growth Factor (FGF), extracellular signal–regulated kinase (ERK) and/or Jun N-terminal kinase (JNK) signaling pathways are associated for the first time with eyespot development. In addition, several genes involved in wound healing and calcium signaling were also found to be associated with eyespots.

Conclusions

Overall, this study provides the identity of many new genes and signaling pathways associated with eyespots, and suggests that the ancient wound healing gene regulatory network may have been co-opted to cells at the center of the pattern to aid in eyespot origins. New transcription factors that may be providing different identities to distinct wing sectors, and genes with sexually dimorphic expression in the eyespots were also identified.

Electronic supplementary material

The online version of this article (10.1186/s12864-017-4175-7) contains supplementary material, which is available to authorized users.

Professor Ernst Bresslau, founder of the Zoology Departments at the Universities of Cologne and Sao Paulo: lessons to learn from his life history

In this article, the life history of the founding father of the departments of Zoology at the Universities of Cologne and Sao Paulo, Prof. Ernst Bresslau, is described on occasion of the establishing of the "Ernst Bresslau Guest Professorship" at the University of Cologne. His main scientific achievements are discussed, in particular his research on the evolutionary origin of the mammary apparatus, in addition to his broad interest in biological topics. Among the many technical advancements that he introduced was the micro slow-motion camera developed together with the Zeiss Company which allowed to film ciliary beats at high speeds.

Innate Immunity and Breast Milk

Human milk is a dynamic source of nutrients and bioactive factors; unique in providing for the human infant's optimal growth and development. The growing infant's immune system has a number of developmental immune deficiencies placing the infant at increased risk of infection. This review focuses on how human milk directly contributes to the infant's innate immunity. Remarkable new findings clarify the multifunctional nature of human milk bioactive components. New research techniques have expanded our understanding of the potential for human milk's effect on the infant that will never be possible with milk formulas. Human milk microbiome directly shapes the infant's intestinal microbiome, while the human milk oligosaccharides drive the growth of these microbes within the gut. New techniques such as genomics, metabolomics, proteomics, and glycomics are being used to describe this symbiotic relationship. An expanded role for antimicrobial proteins/peptides within human milk in innate immune protection is described. The unique milieu of enhanced immune protection with diminished inflammation results from a complex interaction of anti-inflammatory and antioxidative factors provided by human milk to the intestine. New data support the concept of mucosal-associated lymphoid tissue and its contribution to the cellular content of human milk. Human milk stem cells (hMSCs) have recently been discovered. Their direct role in the infant for repair and regeneration is being investigated. The existence of these hMSCs could prove to be an easily harvested source of multilineage stem cells for the study of cancer and tissue regeneration. As the infant's gastrointestinal tract and immune system develop, there is a comparable transition in human milk over time to provide fewer immune factors and more calories and nutrients for growth. Each of these new findings opens the door to future studies of human milk and its effect on the innate immune system and the developing infant.

On the Origin of Complex Adaptive Traits: Progress Since the Darwin Versus Mivart Debate

The evolutionary origin of complex adaptive traits has been a controversial topic in the history of evolutionary biology. Although Darwin argued for the gradual origins of complex adaptive traits within the theory of natural selection, Mivart insisted that natural selection could not account for the incipient stages of complex traits. The debate starting from Darwin and Mivart eventually engendered two opposite views: gradualism and saltationism. Although this has been a long-standing debate, the issue remains unresolved. However, recent studies have interrogated classic examples of complex traits, such as the asymmetrical eyes of flatfishes and leaf mimicry of butterfly wings, whose origins were debated by Darwin and Mivart. Here, I review recent findings as a starting point to provide a modern picture of the evolution of complex adaptive traits. First, I summarize the empirical evidence that unveils the evolutionary steps toward complex traits. I then argue that the evolution of complex traits could be understood within the concept of "reducible complexity." Through these discussions, I propose a conceptual framework for the formation of complex traits, named as reducible-composable multicomponent systems, that satisfy two major characteristics: reducibility into a sum of subcomponents and composability to construct traits from various additional and combinatorial arrangements of the subcomponents. This conceptual framework provides an analytical foundation for exploring evolutionary pathways to build up complex traits. This review provides certain essential avenues for deciphering the origin of complex adaptive traits.

Similar developmental fluctuations of hepato-renal xanthine oxidoreductase gene expression and xanthine oxidase activity in layer and broiler chicken embryos

1. Xanthine oxidase (XO) has many physiological functions associated with the synthesis of both antioxidant (uric acid: UA) and numerous oxidants (e.g. H₂O₂), which makes it an important regulator of the cellular redox potential involving organogenesis. The ontogenetic study of hepatic and renal XO makes a better understanding of the putative role of this enzyme in the development of these tissues. 2. Developmental changes of gene expression of xanthine oxidoreductase (XOR), XO activity and UA content of liver and kidney tissues in both broiler and layer chicken embryos were examined during incubation d 14-21. 3. In both strains, hepatic XOR gene expression peaked on d 21 while renal XOR gene expression did not change. 4. The XO activity was higher in kidney than liver in both strains. Hepatic XO activity of both strains peaked on d 18 and thereafter was decreased on d 21. Renal XO activity peaked on d 18 and from then on did not show any significant changes until d 21 in both strains. 5. The UA content was higher in kidney vs. liver in both strains. The hepatic and renal UA values of the both strains increased significantly from d 14 to d 21. 6. The present results showed dissimilar behaviour of XOR gene expression, XO activity and UA content of liver and kidney tissues in both broiler and layer chicken embryos.

Roles of MicroRNA across Prenatal and Postnatal Periods

Communication between mother and offspring in mammals starts at implantation via the maternal-placental-fetal axis, and continues postpartum via milk targeted to the intestinal mucosa. MicroRNAs (miRNAs), short, noncoding single-stranded RNAs, of about 22 nucleotides in length, are actively involved in many developmental and physiological processes. Here we highlight the role of miRNA in the dynamic signaling that guides infant development, starting from implantation of conceptus and persisting through the prenatal and postnatal periods. miRNAs in body fluids, particularly in amniotic fluid, umbilical cord blood, and breast milk may offer new opportunities to investigate physiological and/or pathological molecular mechanisms that portend to open novel research avenues for the identification of noninvasive biomarkers.

Control of Hoxd gene transcription in the mammary bud by hijacking a preexisting regulatory landscape

Vertebrate Hox genes encode transcription factors operating during the development of multiple organs and structures. However, the evolutionary mechanism underlying this remarkable pleiotropy remains to be fully understood. Here, we show that Hoxd8 and Hoxd9, two genes of the HoxD complex, are transcribed during mammary bud (MB) development. However, unlike in other developmental contexts, their coexpression does not rely on the same regulatory mechanism. Hoxd8 is regulated by the combined activity of closely located sequences and the most distant telomeric gene desert. On the other hand, Hoxd9 is controlled by an enhancer-rich region that is also located within the telomeric gene desert but has no impact on Hoxd8 transcription, thus constituting an exception to the global regulatory logic systematically observed at this locus. The latter DNA region is also involved in Hoxd gene regulation in other contexts and strongly interacts with Hoxd9 in all tissues analyzed thus far, indicating that its regulatory activity was already operational before the appearance of mammary glands. Within this DNA region and neighboring a strong limb enhancer, we identified a short sequence conserved in therian mammals and capable of enhancer activity in the MBs. We propose that Hoxd gene regulation in embryonic MBs evolved by hijacking a preexisting regulatory landscape that was already at work before the emergence of mammals in structures such as the limbs or the intestinal tract.

Temporal Changes of Protein Composition in Breast Milk of Chinese Urban Mothers and Impact of Caesarean Section Delivery

Human breast milk (BM) protein composition may be impacted by lactation stage or factors related to geographical location. The present study aimed at assessing the temporal changes of BM major proteins over lactation stages and the impact of mode of delivery on immune factors, in a large cohort of urban mothers in China. 450 BM samples, collected in three Chinese cities, covering 8 months of lactation were analyzed for α-lactalbumin, lactoferrin, serum albumin, total caseins, immunoglobulins (IgA, IgM and IgG) and transforming growth factor (TGF) β1 and β2 content by microfluidic chip- or ELISA-based quantitative methods. Concentrations and changes over lactation were aligned with previous reports. α-lactalbumin, lactoferrin, IgA, IgM and TGF-β1 contents followed similar variations characterized by highest concentrations in early lactation that rapidly decreased before remaining stable up to end of lactation. TGF-β2 content displayed same early dynamics before increasing again. Total caseins followed a different pattern, showing initial increase before decreasing back to starting values. Serum albumin and IgG levels appeared stable throughout lactation. In conclusion, BM content in major proteins of urban mothers in China was comparable with previous studies carried out in other parts of the world and C-section delivery had only very limited impact on BM immune factors.

Using THz Spectroscopy, Evolutionary Network Analysis Methods, and MD Simulation to Map the Evolution of Allosteric Communication Pathways in c-Type Lysozymes

It is now widely accepted that protein function is intimately tied with the navigation of energy landscapes. In this framework, a protein sequence is not described by a distinct structure but rather by an ensemble of conformations. And it is through this ensemble that evolution is able to modify a protein's function by altering its landscape. Hence, the evolution of protein functions involves selective pressures that adjust the sampling of the conformational states. In this work, we focus on elucidating the evolutionary pathway that shaped the function of individual proteins that make-up the mammalian c-type lysozyme subfamily. Using both experimental and computational methods, we map out specific intermolecular interactions that direct the sampling of conformational states and accordingly, also underlie shifts in the landscape that are directly connected with the formation of novel protein functions. By contrasting three representative proteins in the family we identify molecular mechanisms that are associated with the selectivity of enhanced antimicrobial properties and consequently, divergent protein function. Namely, we link the extent of localized fluctuations involving the loop separating helices A and B with shifts in the equilibrium of the ensemble of conformational states that mediate interdomain coupling and concurrently moderate substrate binding affinity. This work reveals unique insights into the molecular level mechanisms that promote the progression of interactions that connect the immune response to infection with the nutritional properties of lactation, while also providing a deeper understanding about how evolving energy landscapes may define present-day protein function.

Immunization routes in cattle impact the levels and neutralizing capacity of antibodies induced against S. aureus immune evasion proteins

Vaccines against S. aureus bovine mastitis are scarce and show limited protection only. All currently available vaccines are applied via the parenteral (usually intramuscular) route. It is unknown, however, whether this route is the most suitable to specifically increase intramammary immunity to combat S. aureus at the site of infection. Hence, in the present study, immunization via mucosal (intranasal; IN), intramuscular (triangle of the neck; IM), intramammary (IMM) and subcutaneous (suspensory ligament; SC) routes were analyzed for their effects on the quantity of the antibody responses in serum and milk as well as the neutralizing capacity of the antibodies within serum. The experimental vaccine comprised the recombinant S. aureus immune evasion proteins extracellular fibrinogen-binding protein (Efb) and the leukotoxin subunit LukM in an oil-in-water adjuvant combined with a hydrogel and alginate. The highest titer increases for both Efb and LukM specific IgG1 and IgG2 antibody levels in serum and milk were observed following SC/SC immunizations. Furthermore, the harmful effects of Efb and leukotoxin LukMF’ on host-defense were neutralized by serum antibodies in a route-dependent manner. SC/SC immunization resulted in a significant increase in the neutralizing capacity of serum antibodies towards Efb and LukMF’, shown by increased phagocytosis of S. aureus and increased viability of bovine leukocytes. Therefore, a SC immunization route should be considered when aiming to optimize humoral immunity against S. aureus mastitis in cattle.

Persistent Nipple Pain in Breastfeeding Mothers Associated with Abnormal Infant Tongue Movement

Background: Infants of breastfeeding mothers with persistent nipple pain have been shown to apply stronger vacuums to the breast and transfer less milk during one monitored feed. This may be associated with differences in the movement of the tongue. The aim was to analyse the intra-oral nipple shape and movement of the tongue of infants of mothers with and without nipple pain. Methods: Breastfeeding infants of mothers with or without nipple pain were monitored using ultrasound and intra-oral vacuum during one breastfeed. From cine clips of the ultrasound scans measurements were made of the depth of the intra-oral space between the hard-soft palate junction (HSPJ) and the mid-tongue; the distance of the tip of the nipple to the HSPJ; and nipple diameters from the tip to the base. Results: During nutritive sucking, tongue movements of infants of mothers with nipple pain resulted in a smaller intra-oral space (p = 0.040) and restricted nipple expansion compared to controls (p < 0.012). Stronger baseline and peak vacuums compared to controls were confirmed (p = 0.002). Conclusion: In these mothers, nipple pain was associated with restricted infant tongue movement. Ultrasound may complement measurement of intra-oral vacuum in monitoring treatment strategies in breastfeeding women experiencing nipple pain.