ELR+ CXC chemokines in human milk

The inflammatory response to birth requires MyD88 and is driven by both mother and offspring

Birth is an inflammatory event for the newborn, characterized by elevations in interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-α peripherally and/or centrally, as well as changes in brain microglia. However, the mechanism(s) underlying these responses is unknown. Toll-like receptors (TLRs) play crucial roles in innate immunity and initiate inflammatory cascades upon recognition of endogenous or exogenous antigens. Most TLR signaling depends on the adaptor molecule myeloid differentiation primary response 88 (MyD88). We independently varied MyD88 gene status in mouse dams and their offspring to determine whether the inflammatory response to birth depends on MyD88 signaling and, if so, whether that signaling occurs in the offspring, the mother, or both. We find that the perinatal surges in plasma IL-6 and brain expression of TNF-α depend solely on MyD88 gene status of the offspring, whereas postnatal increases in plasma IL-10 and TNF-α depend on MyD88 in both the pup and dam. Interestingly, MyD88 genotype of the dam primarily drives differences in offspring brain microglial density and has robust effects on developmental neuronal cell death. Milk cytokines were evaluated as a possible source of postnatal maternal influence; although we found high levels of CXCL1/GROα and several other cytokines in ingested post-partum milk, their presence did not require MyD88. Thus, the inflammatory response previously described in the late-term fetus and newborn depends on MyD88 (and, by extension, TLRs), with signaling in both the dam and offspring contributing. Unexpectedly, naturally-occuring neuronal cell death in the newborn is modulated primarily by maternal MyD88 gene status.

New Born Calf Serum Can Induce Spheroid Formation in Breast Cancer KAIMRC1 Cell Line

Three-dimensional (3D) cell culture systems have become very popular in the field of drug screening and discovery. There is an immense demand for highly efficient and easy methods to produce 3D spheroids in any cell format. We have developed a novel and easy method to produce spheroids from the newly isolated KAIMRC1 cell line in vitro. It can be used as a 3D model to study proliferation, differentiation, cell death, and drug response of cancer cells. Our procedure requires growth media supplemented with 10% new born calf serum (NBCS) and regular cell culture plates to generate KAIMRC1 spheroids without the need for any specialized 3D cell culture system. This procedure generates multiple spheroids within a 12–24-h culture. KAIMRC1 spheroids are compact, homogeneous in size and morphology with a mean size of 55.8 µm (±3.5). High content imaging (HCI) of KAIMRC1 spheroids treated with a panel of 240 compounds resulted in the identification of several highly specific compounds towards spheroids. Immunophenotyping of KAIMRC1 spheroids revealed phosphorylation of FAK, cJUN, and E-cadherin, which suggests the involvement of JNK/JUN pathway in the KAIMRC1 spheroids formation. Gene expression analysis showed upregulation of cell junction genes, GJB3, DSC1, CLDN5, CLDN8, and PLAU. Furthermore, co-culture of KAIMRC1 cells with primary cancer-associated-fibroblasts (CAFs) showcased the potential of these cells in drug discovery application.

Characterization and comparative analysis of transcriptional profiles of porcine colostrum and mature milk at different parities

BACKGROUND

Porcine milk is a complex fluid, containing a myriad of immunological, biochemical, and cellular components, made to satisfy the nutritional requirements of the neonate. Whole milk contains many different cell types, including mammary epithelial cells, neutrophils, macrophages, and lymphocytes, as well nanoparticles, such as milk exosomes. To-date, only a limited number of livestock transcriptomic studies have reported sequencing of milk. Moreover, those studies focused only on sequencing somatic cells as a proxy for the mammary gland with the goal of investigating differences in the lactation process. Recent studies have indicated that RNA originating from multiple cell types present in milk can withstand harsh environments, such as the digestive system, and transmit regulatory molecules from maternal to neonate. Transcriptomic profiling of porcine whole milk, which is reflective of the combined cell populations, could help elucidate these mechanisms. To this end, total RNA from colostrum and mature milk samples were sequenced from 65 sows at differing parities. A stringent bioinformatic pipeline was used to identify and characterize 70,841 transcripts.

RESULTS

The 70,841 identified transcripts included 42,733 previously annotated transcripts and 28,108 novel transcripts. Differential gene expression analysis was conducted using a generalized linear model coupled with the Lancaster method for P-value aggregation across transcripts. In total, 1667 differentially expressed genes (DEG) were identified for the milk type main effect, and 33 DEG were identified for the milk type x parity interaction. Several gene ontology (GO) terms related to immune response were significant for the milk type main effect, supporting the well-known fact that immunoglobulins and immune cells are transferred to the neonate via colostrum.

CONCLUSIONS

This is the first study to perform global transcriptome analysis from whole milk samples in sows from different parities. Our results provide important information and insight into synthesis of milk proteins and innate immunity and potential targets for future improvement of swine lactation and piglet development.

Immunomodulatory Effects of Human Colostrum and Milk

The immune system is not fully developed in human neonates and infants; breastfeeding is important in this stage as the bioactive components of human breast milk are known to have anti-microbial, anti-inflammatory, and immunomodulatory effects, and can therefore contribute to an infant's immunity against allergies, asthma, autoimmune diseases, and inflammatory bowel disease. Herein, the positive effect on the immune system by human colostrum and milk are reviewed.

The impact of parturition induction with cloprostenol on immunological parameters in the sow colostrum

BACKGROUND

Farrowing induction with prostaglandin F2 analogue cloprostenol is commonly used on commercial farms to manage the timing of farrowing. When labour induction is applied, the questions arise about possible side effects of such a hormonal intervention on physiological processes connected with labour and lactation, including colostral immunity.

RESULTS

In this study, immune cells composition, lysozyme concentration, complement bacteriolytic activity and proinflamatory (GM-CSF2, IL-1β, IL-6, a TNFα) and anti-inflammatory (IL-4, IL-10, TGFβ1 a TGFβ2) cytokines were measured in colostrum samples from sows farrowing naturally (NP) and from sows with farrowing induced using cloprostenol administration on day 113 of gestation (IP). A significantly higher proportion of lymphocytes was found in colostrum of induced sows compared to colostrum of non-induced sows. No significant differences between NP and IP were found in complement activity, in the proportions of granulocytes, macrophages and lymphocyte subpopulations. Lower lysozyme concentration and higher IL-1β, IL-6, TGFβ1 and TNFα concentrations were found in IP sow colostrum compared to colostrum from NP sows.

CONCLUSIONS

An increased proportion of colostral lymphocytes can positively influence the cellular immunity transmission from sow to her offspring. On the other hand, a lower lysozyme concentration can adversely affect newborn's intestinal immunity, as well as changes in cytokine concentrations can have an adverse effect on newborn piglet intestinal epithelium development and its defence function.

Bovine Colostrum in Prevention of Necrotizing Enterocolitis and Sepsis in Very Low Birth Weight Neonates: A Randomized, Double-blind, Placebo-controlled Pilot Trial

OBJECTIVE

To study the efficacy of bovine colostrum in prevention of necrotizing enterocolitis (NEC) and sepsis in very low birth weight (VLBW) infants.

STUDY DESIGN

Randomized, double-blind, placebo-controlled pilot trial.

PARTICIPANTS

Neonates with birth weight ≤1500 g, gestation ≤32 weeks and postnatal age ≤96 h.

INTERVENTION

Enteral bovine colostrum or placebo, four times a day, till 21 days of life or discharge or death.

MAIN OUTCOME MEASURES

Definite NEC. Secondary outcomes included sepsis, mortality and stool interleukin-6 (IL-6) levels.

RESULTS

Of the total 86 subjects (43 in each group), there were no statistically significant in the main outcome measures. In the colostrum group, there were trends toward higher stool IL-6 values and higher incidence of ileus and radiological signs of NEC.

CONCLUSION

The use of prophylactic enteral bovine colostrum in VLBW infants shows a trend toward increased stool IL-6 and features of NEC. We were unable to detect clinical benefits.

Cytokines and growth factors in the developing intestine and during necrotizing enterocolitis

Cytokines and growth factors play diverse roles in the uninflamed fetal/neonatal intestinal mucosa and in the development of inflammatory bowel injury during necrotizing enterocolitis (NEC). During gestational development and the early neonatal period, the fetal/premature intestine is exposed to high levels of many "inflammatory" cytokines and growth factors, first via swallowed amniotic fluid in utero and then, after birth, in colostrum and mother's milk. This article reviews the dual, seemingly counter-intuitive roles of cytokines, where these agents play a "trophic" role and promote maturation of the uninflamed mucosa, but can also cause inflammation and promote intestinal injury during NEC.

Role of Maternal Allergy on Immune Markers in Colostrum and Secretory Immunoglobulin A in Stools of Breastfed Infants

BACKGROUND

Although protection against infectious diseases has been observed among breastfed infants as compared to formula-fed infants, possible benefits of breastfeeding by allergic mothers for allergy prevention remain controversial.

OBJECTIVES

The aims of this study were to determine whether maternal allergy would influence immune markers (secretory immunoglobulin A [sIgA], interleukin-8 [IL-8], soluble CD14 [sCD14]) in colostrum and the associations between maternal allergy and fecal sIgA levels in breastfed infants.

METHODS

Study subjects were enrolled from the Prediction of Allergies in Taiwanese Children (PATCH) birth cohort study. Colostrum samples were obtained from 98 lactating mothers. Stool samples were collected from 108 infants within 5 days after birth and at 2 and 4 months of age. We compared concentrations of sIgA, IL-8, and sCD14 in colostrum between mothers with and without a history of allergic disease and allergic sensitization. We also compared fecal sIgA levels between breastfed and formula-fed infants and between infants with allergic and nonallergic mothers.

RESULTS

The sIgA concentrations were significantly higher in colostrum from allergic mothers than from nonallergic mothers (P = .01) and from allergic mothers who were immunoglobulin E (IgE) sensitized compared to nonallergic mothers who were not IgE sensitized (P = .023). Breastfed infants had significantly higher fecal sIgA levels as compared to formula-fed infants, regardless of whether their lactating mothers had an allergy (P < .05).

CONCLUSION

We found that breastfeeding is associated with increased infants' fecal sIgA levels and may have potential protective effects to the infants during the first 4 months of life, regardless of whether their lactating mothers have allergies.

The Mammary Gland in Mucosal and Regional Immunity

The mammary gland (MG) lacks a mucosa but is part of the mucosal immune system because of its role in passive mucosal immunity. The MG is not an inductive site for mucosal immunity. Rather, synthesis of immunoglobulin (Ig)A by plasma cells stimulated at distal inductive sites dominate in the milk of rodents, humans, and swine whereas IgG1 derived from serum predominates in ruminants. Despite the considerable biodiversity in the role of the MG, IgG passively transfers the maternal systemic immunological experience whereas IgA transfers the mucosal immunological experience. Although passive antibodies are protective, they and other lacteal constituents can be immunoregulatory. Immune protection of the MG largely depends on the innate immune system; the monocytes–macrophages group together with intraepithelial lymphocytes is dominant in the healthy gland. An increase in somatic cells (neutrophils) and various interleukins signal infection (mastitis) and a local immune response in the MG. The major role of the MG to mucosal immunity is the passive immunity supplied to the suckling neonate.

Maternal surfactant protein A influences the immunoprotective properties of milk in a murine model

BACKGROUND

Maternal surfactant protein A (SP-A), a collectin with innate immune system function, is critical to newborn mouse survival preventing bacterial peritonitis associated with a nonhygienic environmental exposure. We hypothesized that SP-A improves newborn survival by optimizing milk immunoprotection.

METHODS

Regional (lung) and systemic (milk and serum) immunologic responses to a novel antigen, 2,4-dintirophenyl keyhole limpet hemocyanin (DNP-KLH), and to a nonhygienic environment were evaluated in wild-type (WT) and SP-A null murine dams. Cross-fostering pups assessed the impact of milk on newborn survival.

RESULTS

Maternal SP-A optimized antigen-specific milk secretory IgA (sIgA) production following the DNP-KLH exposure. Milk total and environment-specific sIgA production was not dependent on maternal SP-A in the nonhygienic exposure. At baseline, SP-A null milk contained physiologically meaningful increases in two proinflammatory cytokines compared with WT milk. The lack of SP-A plus the nonhygienic environmental exposure synergistically increased the number of proinflammatory cytokines contained in milk. Finally, the SP-A null genotype decreased pup survival during a nonhygienic environmental exposure.

CONCLUSION

Maternal SP-A impacts milk sIgA and cytokine content, and is associated with improved newborn health.

Differential roles of CXCL2 and CXCL3 and their receptors in regulating normal and asthmatic airway smooth muscle cell migration

Structural cell migration plays a central role in the pathophysiology of several diseases, including asthma. Previously, we established that IL-17-induced (CXCL1, CXCL2, and CXCL3) production promoted airway smooth muscle cell (ASMC) migration, and consequently we sought to investigate the molecular mechanism of CXC-induced ASMC migration. Recombinant human CXCL1, CXCL2, and CXCL3 were used to assess migration of human primary ASMCs from normal and asthmatic subjects using a modified Boyden chamber. Neutralizing Abs or small interfering RNA (siRNA) knockdown and pharmacological inhibitors of PI3K, ERK1/2, and p38 MAPK pathways were used to investigate the receptors and the signaling pathways involved in CXC-induced ASMC migration, respectively. We established the ability of CXCL2 and CXCL3, but not CXCL1, to induce ASMC migration at the tested concentrations using normal ASMCs. We found CXCL2-induced ASMC migration to be dependent on p38 MAPK and CXCR2, whereas CXCL3-induced migration was dependent on p38 and ERK1/2 MAPK pathways via CXCR1 and CXCR2. While investigating the effect of CXCL2 and CXCL3 on asthmatic ASMC migration, we found that they induced greater migration of asthmatic ASMCs compared with normal ones. Interestingly, unlike normal ASMCs, CXCL2- and CXCL3-induced asthmatic ASMC migration was mainly mediated by the PI3K pathway through CXCR1. In conclusion, our results establish a new role of CXCR1 in ASMC migration and demonstrate the diverse mechanisms by which CXCL2 and CXCL3 mediate normal and asthmatic ASMC migration, suggesting that they may play a role in the pathogenesis of airway remodeling in asthma.

Human milk composition: nutrients and bioactive factors

This article provides an overview of the composition of human milk, its variation, and its clinical relevance. The composition of human milk is the biological norm for infant nutrition. Human milk also contains many hundreds to thousands of distinct bioactive molecules that protect against infection and inflammation and contribute to immune maturation, organ development, and healthy microbial colonization. Some of these molecules (eg, lactoferrin) are being investigated as novel therapeutic agents. Human milk changes in composition from colostrum to late lactation, within feeds, by gestational age, diurnally, and between mothers. Feeding infants with expressed human milk is increasing.

Presence of CTAK/CCL27, MCP-3/CCL7 and LIF in human colostrum and breast milk

Human colostrum and breast milk are known to contain high levels of cytokines and chemokines, which are thought to contribute to the development of the newborn. The aim of this study was to investigate the difference in the presence and levels of 21 soluble cytokines and chemokines in paired samples of human colostrum (day 2 after delivery) and breast milk (day 4-5 after delivery) by using the multiplex technology. Of the 21 cytokine investigated in 10 pairs of samples, only β-NGF was absent in both colostrum and milk, while INF-α2, SCF and TNF-β were present in colostrum but not in human milk. As a general rule, colostrum contained higher concentrations of cytokines and chemokines with respect to breast milk. The majority of cytokines, detected in colostrum alone or in colostrum and human milk (IL-1α, IL-2Rα, IL-3, IL-16, IL-18, GRO-α, HGF, IFN-α2, M-CSF, MIF, MIG, TNF-β, SDF-1α, TRAIL) have been described in previous studies, while for the first time we describe the presence of additional cytokines either in colostrum alone (SCF) or in both colostrum and breast milk (CTAK/CCL27, MCP-3/CCL7, LIF). Our data confirm and expand previous studies showing that some cytokines/chemokines, which might contribute to the development of the gastro-intestinal and nervous systems, are overexpressed in human colostrum and breast milk, and might contribute to the development of these systems.

Antimicrobial chemokines

Chemokines are best known for their classic leukocyte chemotactic activity, which is critical for directing the immune response to sites of infection and injury. However, recent studies have suggested that at least some chemokines may also interfere with infectious agents directly. Antimicrobial chemokines tend to contain amphipathic alpha helical secondary structure, and broad-spectrum activity against both Gram-positive and Gram negative bacteria, as well as fungi. Conversely, several bacteria have been identified that possess mechanisms for specifically blocking the antimicrobial activities of chemokines. Although the precise mechanisms by which chemokines and microbes disarm one another in vitro remain unknown, there is now emerging evidence in vivo that such interactions may be biologically significant. More research will be needed to determine whether chemokines with direct antimicrobial activity may be translated into a novel class of antibiotics.

The Tumor-Promoting Flow of Cells Into, Within and Out of the Tumor Site: Regulation by the Inflammatory Axis of TNFα and Chemokines

Tumors are dynamic organs, in which active processes of cell motility affect disease course by regulating the composition of cells at the tumor site. While sub-populations of tumor-promoting leukocytes are recruited inward and endothelial cell migration stands in the basis of vascular branching throughout the tumor, cancer cells make their way out of the primary site towards specific metastatic sites. This review describes the independent and cross-regulatory roles of inflammatory chemokines and of the inflammatory cytokine tumor necrosis factor α (TNFα) in determining cell motility processes that eventually have profound effects on tumor growth and metastasis. First, the effects of inflammatory chemokines such as CCL2 (MCP-1), CCL5 (RANTES) and CXCL8 (IL-8) are described, regulating the inward flow of leukocyte sub-populations with pro-tumoral activities, such as tumor-associated macrophages (TAM), myeloid-derived suppressor cells (MDSC), tumor-associated neutrophils (TAN), Th17 cells and Tregs. Then, the ability of inflammatory chemokines to induce endothelial cell migration, sprouting and tube formation is discussed, with its implications on tumor angiogenesis. This part is followed by an in depth description of the manners by which TNFα potentiates the above activities of the inflammatory chemokines, alongside with its ability to directly induce migratory processes in the tumor cells thus promoting metastasis. Note worthy is the ability of TNFα to induce in the tumor cells the important process of epithelial-to-mesenchymal transition (EMT). Emphasis is given to the ability of TNFα to establish an inflammatory network with the chemokines, and in parallel to form a cell re-modeling network together with transforming growth factor β (TGFβ). The review concludes by discussing the implications of such networks on disease course, and on the future design of therapeutic measures in cancer.

Early detection of tumor cells by innate immune cells leads to T(reg) recruitment through CCL22 production by tumor cells

In breast carcinomas, patient survival seems to be negatively affected by the recruitment of regulatory T cells (T(reg)) within lymphoid aggregates by CCL22. However, the mechanisms underpinning this process, which may be of broader significance in solid tumors, have yet to be described. In this study, we determined how CCL22 production is controlled in tumor cells. In human breast carcinoma cell lines, CCL22 was secreted at low basal levels that were strongly increased in response to inflammatory signals [TNF-α, IFN-γ, and interleukin (IL)-1β], contrasting with CCL17. Primary breast tumors and CD45(+) infiltrating immune cells appeared to cooperate in driving CCL22 secretion, as shown clearly in cocultures of breast tumor cell lines and peripheral blood mononuclear cells (PBMC) or their supernatants. We determined that monocyte-derived IL-1β and TNF-α are key players as monocyte depletion or neutralization of these cytokines attenuated secretion of CCL22. However, when purified monocytes were used, exogenous human IFN-γ was also required to generate this response suggesting a role for IFN-γ-producing cells within PBMCs. In this setting, we found that human IFN-γ could be replaced by the addition of (i) IL-2 or K562-activated natural killer (NK) cells or (ii) resting NK cells in the presence of anti-MHC class I antibody. Taken together, our results show a dialogue between NK and tumor cells leading to IFN-γ secretion, which in turn associates with monocyte-derived IL-1β and TNF-α to drive production of CCL22 by tumor cells and subsequent recruitment of T(reg). As one validation of this conclusion in primary breast tumors, we showed that NK cells and macrophages tend to colocalize within tumors. In summary, our findings suggest that at early times during tumorigenesis, the detection of tumor cells by innate effectors (monocytes and NK cells) imposes a selection for CCL22 secretion that recruits T(reg) to evade this early antitumor immune response.

Premature delivery influences the immunological composition of colostrum and transitional and mature human milk

Human breast milk is the ideal nutrition for the newborn, and in addition to its nutritional contribution, necessary for infant growth and development, it contains various immune bioactive factors that confer some of the numerous beneficial effects of breastfeeding. The current study analyzed the concentrations of IgA, growth factors such as epidermal growth factor (EGF), TGFβ1, and TGFβ2, cytokines IL-6, IL-8, IL-10, IL-13, and TNFα, and TNF-receptor I (TNF-RI) in colostrum and transitional and mature milk from mothers with mature, premature, and very premature infants. Human milk samples were collected from mothers delivering at term (T), preterm (PT), and very preterm (VPT). Milk from all the mothers was collected at 3 different time points after delivery corresponding to colostrum and transitional and mature milk. After obtaining milk whey, IgA, EGF, TGFβ1, and TGFβ2 were determined by ELISA and IL-6, IL-8, IL-10, IL-13, TNFα and TNF-RI by cytometric bead array immunoassay. The colostrum of the PT group was extremely rich in most of the factors studied, but higher concentrations than in the T group were only found for IL-6 (P = 0.051), TGFβ1, and TGFβ2 (P < 0.05). Conversely, the colostrum of the VPT group had lower concentrations of IgA, IL-8, IL-10, and TNFα than those in the T group (P < 0.05). Results suggest that maternal lactogenic compensatory mechanisms accelerating the development of immature breast-fed preterm infants may take effect only after wk 30 of gestation.

Chemokines: key players in cancer progression and metastasis

Instructed cell migration is a fundamental component of various biological systems and is critical to the pathogenesis of many diseases including cancer. Role of chemokines in providing navigational cues to migrating cancer cells bearing specific receptors is well established. However, functional mechanisms of chemokine are not well implicit, which is crucial for designing new therapeutics to control tumor growth and metastasis. Multiple functions and mode of actions have been advocated for chemokines and their receptors in the progression of primary and secondary tumors. In this review, we have discussed current advances in understanding the role of the chemokines and their corresponding receptor in tumor progression and metastasis.

TGF-β2 suppresses macrophage cytokine production and mucosal inflammatory responses in the developing intestine

BACKGROUND & AIMS

Premature neonates are predisposed to necrotizing enterocolitis (NEC), an idiopathic, inflammatory bowel necrosis. We investigated whether NEC occurs in the preterm intestine due to incomplete noninflammatory differentiation of intestinal macrophages, which increases the risk of a severe mucosal inflammatory response to bacterial products.

METHODS

We compared inflammatory properties of human/murine fetal, neonatal, and adult intestinal macrophages. To investigate gut-specific macrophage differentiation, we next treated monocyte-derived macrophages with conditioned media from explanted human fetal and adult intestinal tissues. Transforming growth factor-β (TGF-β) expression and bioactivity were measured in fetal/adult intestine and in NEC. Finally, we used wild-type and transgenic mice to investigate the effects of deficient TGF-β signaling on NEC-like inflammatory mucosal injury.

RESULTS

Intestinal macrophages in the human preterm intestine (fetus/premature neonate), but not in full-term neonates and adults, expressed inflammatory cytokines. Macrophage cytokine production was suppressed in the developing intestine by TGF-β, particularly the TGF-β(2) isoform. NEC was associated with decreased tissue expression of TGF-β(2) and decreased TGF-β bioactivity. In mice, disruption of TGF-β signaling worsened NEC-like inflammatory mucosal injury, whereas enteral supplementation with recombinant TGF-β(2) was protective.

CONCLUSIONS

Intestinal macrophages progressively acquire a noninflammatory profile during gestational development. TGF-β, particularly the TGF-β(2) isoform, suppresses macrophage inflammatory responses in the developing intestine and protects against inflammatory mucosal injury. Enterally administered TGF-β(2) protected mice from experimental NEC-like injury.

Primary human mammary epithelial cells endocytose HIV-1 and facilitate viral infection of CD4+ T lymphocytes

The contribution of mammary epithelial cells (MEC) to human immunodeficiency virus type 1 (HIV-1) in breast milk remains largely unknown. While breast milk contains CD4(+) cells throughout the breast-feeding period, it is not known whether MEC directly support HIV-1 infection or facilitate infection of CD4(+) cells in the breast compartment. This study evaluated primary human MEC for direct infection with HIV-1 and for indirect transfer of infection to CD4(+) target cells. Primary human MEC were isolated and assessed for expression of HIV-1 receptors. MEC were exposed to CCR5-, CXCR4- and dual-tropic strains of HIV-1 and evaluated for viral reverse transcription and integration and productive viral infection. MEC were also tested for the ability to transfer HIV to CD4(+) target cells and to activate resting CD4(+) T cells. Our results demonstrate that MEC express HIV-1 receptor proteins CD4, CCR5, CXCR4, and galactosyl ceramide (GalCer). While no evidence for direct infection of MEC was found, HIV-1 virions were observed in MEC endosomal compartments. Coculture of HIV-exposed MEC resulted in productive infection of activated CD4(+) T cells. In addition, MEC secretions increased HIV-1 replication and proliferation of infected target cells. Overall, our results indicate that MEC are capable of endosomal uptake of HIV-1 and can facilitate virus infection and replication in CD4(+) target cells. These findings suggest that MEC may serve as a viral reservoir for HIV-1 and may enhance infection of CD4(+) T lymphocytes in vivo.

Consequences of interference of milk with chemoattractants for enzyme-linked immunosorbent assay quantifications

Concentrations of the chemoattractants CXCL1, CXCL2, CXCL3, CXCL8, and C5a in milk were reduced by the preparation of milk whey by high-speed centrifugation or with rennet. About half of the chemoattractants (35 to 65%) were associated with the casein micelle sediment, except when whey was prepared by acidification. Consequently, quantification of chemoattractants should be carried out preferentially with skimmed milk samples or, whenever whey is needed, with acidic whey samples. The interference of milk or milk whey with the enzyme-linked immunosorbent assays (ELISAs) used to quantify the chemoattractants was moderate, as long as tetramethylbenzidine (TMB), not ABTS [2,2'-azino-bis-(3-ethylbenzthiazoline-sulfonate)], was used as the substrate of peroxidase. These considerations will help to assess more precisely a component of the immune response of the mammary gland to infection.

Humoral and cellular factors of maternal immunity in swine

Immunoglobulins cannot cross the placenta in pregnant sows. Neonatal pigs are therefore agammaglobulinemic at birth and, although immunocompetent, they cannot mount rapid immune responses at systemic and mucosal sites. Their survival depends directly on the acquisition of maternal immunity via colostrum and milk. Protection by maternal immunity is mediated by a number of factors, including specific systemic humoral immunity, involving mostly maternal IgG transferred from blood to colostrum and typically absorbed within the first 36 h of life. Passive mucosal immunity involves local humoral immunity, including the production of secretory IgA (sIgA), which is transferred principally via milk until weaning. The mammary gland (MG) produces sIgA, which is, then secreted into the milk via the poly-Ig receptor (pIgR) of epithelial cells. These antibodies are produced in response to intestinal and respiratory antigens, including pathogens and commensal organisms. Protection is also mediated by cellular immunity, which is transferred via maternal cells present in mammary secretions. The mechanisms underlying the various immunological links between MG and the mucosal surfaces involve hormonally regulated addressins and chemokines specific to these compartments. The enhancement of colostrogenic immunity depends on the stimulation of systemic immunity, whereas the enhancement of lactogenic immunity depends on appropriate stimulation at induction sites, an increase in cell trafficking from the gut and upper respiratory tract to the MG and, possibly, enhanced immunoglobulin production at the effector site and secretion in milk. In addition, mammary secretions provide factors other than immunoglobulins that protect the neonate and regulate the development of mucosal immunity--a key element of postnatal adaptation to environmental antigens.

Low intensity shear stress increases endothelial ELR+ CXC chemokine production via a focal adhesion kinase-p38{beta} MAPK-NF-{kappa}B pathway

CXC chemokines with a glutamate-leucine-arginine (ELR) tripeptide motif (ELR(+) CXC chemokines) play an important role in leukocyte trafficking into the tissues. For reasons that are not well elucidated, circulating leukocytes are recruited into the tissues mainly in small vessels such as capillaries and venules. Because ELR(+) CXC chemokines are important mediators of endothelial-leukocyte interaction, we compared chemokine expression by microvascular and aortic endothelium to investigate whether differences in chemokine expression by various endothelial types could, at least partially, explain the microvascular localization of endothelial-leukocyte interaction. Both in vitro and in vivo models indicate that ELR(+) CXC chemokine expression is higher in microvascular endothelium than in aortic endothelial cells. These differences can be explained on the basis of the preferential activation of endothelial chemokine production by low intensity shear stress. Low shear activated endothelial ELR(+) CXC chemokine production via cell surface heparan sulfates, beta(3)-integrins, focal adhesion kinase, the mitogen-activated protein kinase p38beta, mitogen- and stress-associated protein kinase-1, and the transcription factor.

Constitutive expression of the antibacterial CXC chemokine GCP-2/CXCL6 by epithelial cells of the male reproductive tract

The reproductive tract is continuously challenged by potential pathogens present in the environment. Therefore, robust host defense mechanisms are essential both for the health of the individual and for fertilization. Antibiotic innate immunity peptides possess broad antimicrobial activity. Recently, we found that the CXC chemokine, granulocyte chemotactic protein (GCP)-2/CXCL6, possesses antibacterial activity. In the present study, we investigated, therefore, the presence of GCP-2/CXCL6 in the human male reproductive system. GCP-2/CXCL6 was detected at 19nM (mean; range: 5-47nM; n=14) in seminal plasma of fertile donors, i.e. at levels more than 100 times higher than those previously reported for the related chemokine IL-8/CXCL8. No GCP-2/CXCL6 could be detected in blood plasma of healthy donors, indicating local production in the male reproductive tract. In vasectomized donors, significantly lower levels of GCP-2/CXCL6 were found (mean: 3nM; range 2-7nM; n=7), demonstrating that the testis and epididymis contribute significantly to the GCP-2/CXCL6 content of seminal plasma. Strong expression of GCP-2/CXCL6 was found in the epithelium of the testis, epididymis and seminal vesicles, while the prostate epithelium showed weak expression, as determined by immunohistochemistry. A biological function is suggested, viz. at concentrations of the order of those found in seminal plasma, GCP-2/CXCL6 has antibacterial activity against the urogenital pathogen Neisseria gonorrhoeae. GCP-2/CXCL6 in seminal plasma may play roles in both host defense of the male urogenital tract and during fertilization.

Host factors in amniotic fluid and breast milk that contribute to gut maturation

The gut represents a complex organ system with regional differences, which reflect selective digestive and absorptive functions that change constantly in response to bodily requirements and the outside milieu. As a barrier to the external environment, gut epithelium must be renewed rapidly and repeatedly. Growth and renewal of gut epithelial cells is dependent on controlled cell stimulation and proliferation by a number of signaling processes and agents, including gut peptides-both endogenous and exogenous sources. This cascade of events begins during fetal development; with the ingestion of amniotic fluid, this process is enhanced and continued during infancy and early childhood through the ingestion of human milk. Events influenced by amniotic fluid during fetal development and those influenced by human milk that unfold after birth and early childhood to render the gut mature are presented.

The human CXC chemokine granulocyte chemotactic protein 2 (GCP-2)/CXCL6 possesses membrane-disrupting properties and is antibacterial

Granulocyte chemotactic protein 2 (GCP-2)/CXCL6 is a CXC chemokine expressed by macrophages and epithelial and mesenchymal cells during inflammation. Through binding and activation of its receptors (CXCR1 and CXCR2), it exerts neutrophil-activating and angiogenic activities. Here we show that GCP-2/CXCL6 itself is antibacterial. Antibacterial activity against gram-positive and gram-negative pathogenic bacteria of relevance to mucosal infections was seen at submicromolar concentrations (minimal bactericidal concentration at which 50% of strains tested were killed, 0.063 +/- 0.01 to 0.37 +/- 0.03 muM). In killed bacteria, GCP-2/CXCL6 associated with bacterial surfaces, which showed membrane disruption and leakage. A structural prediction indicated the presence of three antiparallel NH(2)-terminal beta-sheets and a short amphipathic COOH-terminal alpha-helix; the latter feature is typical of antimicrobial peptides. However, when the synthetic derivatives corresponding to the NH(2)-terminal (50 amino acids) and COOH-terminal (19 amino acids, corresponding to the putative alpha-helix) regions were compared, higher antibacterial activity was observed for the NH(2)-terminus-derived peptide, indicating that the holopeptide is necessary for full antibacterial activity. An artificial model of bacterial membranes confirmed these findings. The helical content of GCP-2/CXCL6 in the presence or absence of lipopolysaccharide or negatively charged membranes was studied by circular dichroism. As with many antibacterial peptides, membrane disruption by GCP-2/CXCL6 was dose-dependently reduced in the presence of NaCl, which, we here demonstrate, inhibited the binding of the peptide to the bacterial surface. Compared with CXC chemokines ENA-78/CXCL5 and NAP-2/CXCL7, GCP-2/CXCL6 showed a 90-fold-higher antibacterial activity. Taken together, GCP/CXCL6, in addition to its chemotactic and angiogenic properties, is likely to contribute to direct antibacterial activity during localized infection.

Chemokines: novel targets for breast cancer metastasis

Recent studies have highlighted the possible involvement of chemokines and their receptors in breast cancer progression and metastasis. Chemokines and their receptors constitute a superfamily of signalling factors whose prognosis value in breast cancer progression remains unclear. We will examine here the expression pattern of chemokines and their receptors in mammary gland physiology and carcinogenesis. The nature of the cells producing chemokines or harboring chemokine receptors appears to be crucial in certain conditions for example, the infiltration of the primary tumor by leukocytes and angiogenesis. In addition, chemokines, their receptors and the interaction with glycosaminoglycan (GAGs) are key players in the homing of cancer cells to distant metastasis sites. Several lines of evidence, including in vitro and in vivo models, suggest that the mechanism of action of chemokines in cancer development involves the modulation of proliferation, apoptosis, invasion, leukocyte recruitment or angiogenesis. Furthermore, we will discuss the regulation of chemokine network in tumor neovascularity by decoy receptors. The reasons accounting for the deregulation of chemokines and chemokine receptors expression in breast cancer are certainly crucial for the comprehension of chemokine role in breast cancer and are in several cases linked to estrogen receptor status. The targeting of chemokines and chemokine receptors by antibodies, small molecule antagonists, viral chemokine binding proteins and heparins appears as promising tracks to develop therapeutic strategies. Thus there is significant interest in developing strategies to antagonize the chemokine function, and an opportunity to interfere with metastasis, the leading cause of death in most patients.

Human intrahepatic biliary epithelial cell as a possible modulator of hepatic regeneration: Potential role of biliary epithelial cell for hepatic remodeling in vivo

BACKGROUND

During liver regeneration, the process of hepatic wound healing, a complex cascade of inflammatory signals, recruit inflammatory cells, stimulate hepatobiliary cell proliferation, direct cell migration and induce vascularization to restore tissue integrity, irrespective of its etiology. This might also be the case in cholangiopathies, in which the initial target is the branch of the intrahepatic biliary tree; that is, primary biliary cirrhosis. Previous studies about biliary wound healing focused mainly on the inducers of compensatory biliary proliferation following bile duct insult. Nevertheless, the microenvironment around biliary wound healing responses, which in turn might affect hepatic remodeling, possibly by biliary epithelial cells themselves via paracrine manner, is still less known.

METHODS

In this study, we defined the humoral factors that are released from human intrahepatic biliary epithelial cell lines (HIBEC) with human cytokine array, and reviewed their relevance according to the previous published work.

RESULTS

Conditioned medium of HIBEC were revealed to be rich in multiple cytokines and chemokines, including ELR(+)CXC chemokines, such as interleukin-8/CXCL8, growth-related oncoprotein (GRO), epithelial neutrophil chemoattractant (ENA-78), known chemoattractants with a wide range of non-leukocytic activities. Subsequent enzyme-linked immunosorbent assay analyses confirmed that the secretion was commonly observed in various culture conditions and in both an apical and basolateral direction.

CONCLUSIONS

Considering that some of these factors had been already reported to have direct autocrine mitogenic influence on HIBEC, these findings could further strengthen an active role of HIBEC as a modulator of hepatic regeneration, through its biological reactivity on inflamed milieu.

Cytokines in human breast cyst fluid

Gross cystic breast disease is a common benign disorder in which palpable cysts occur in the breast and are normally treated by aspiration of the contents. The cysts are classified as either Type 1, containing a high level of potassium ions and a low level of sodium ions, or as Type 2, with low potassium and high sodium ion concentrations. Steroid sulphatase activity in MDA-MB-231 and MCF-7 cell lines is regulated by exogenous breast cyst fluid (BCF), possibly because of cytokines in the BCF. A screening method was used to determine the range of cytokines in eight BCFs, four of each type. This was an array system, which uses antibodies immobilised on a membrane to qualitatively detect 79 different cytokines or growth factors. Nine cytokines were detected well above background levels: all were found in both types of BCF, but only epidermal growth factor (EGF) was higher in Type 1. All the other factors were higher in Type 2 BCF. Two of these cytokines, IL-6 and EGF, have previously been suggested to affect steroid sulphatase expression and several (MIP-1beta, IL-8, NAP-2) are known to affect MCF-7 cell chemotaxis. In addition two cytokines were measured by ELISA in 57 BCFs, and both IL-1beta and IL-13 were found in BCF, with significantly higher amounts of IL-1beta in Type 1 than Type 2 BCF (35.5+/-4.4 pg/ml versus 9.9+/-2.9 pg/ml).

Differential cytokine and chemokine responses of bovine mammary epithelial cells to Staphylococcus aureus and Escherichia coli

We studied the inflammatory and immune responses of bovine mammary epithelial cells (bMEC) infected by mastitis isolates of Staphylococcus aureus. Primary cultures of bMEC were co-incubated separately with three strains of S. aureus and one strain of Escherichia coli. Transcriptional levels and/or protein release of interleukin-8 (IL-8), growth related oncogene alpha (GRO-alpha), growth related oncogene beta (GRO-beta), tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), transforming growth factor beta1 (TGF-beta1) and interleukin-10 (IL-10) were measured at 3, 10 and 24h post-infection (PI). The results indicated that at earlier hours of co-culture, bMEC infected with S. aureus or E. coli expressed more IL-1beta, TNF-alpha, IL-8 and GRO-alpha mRNA than uninfected bMEC. Furthermore, infected bMEC released more TNF-alpha, IL-8, GRO-alpha and GRO-beta proteins than uninfected bMEC. However, differential transcription and release of some cytokines/chemokines from bMEC was observed according to the strain of S. aureus and bacteria Gram type. In conclusion, bMEC did not show an anti-inflammatory potential through IL-10 or TGF-beta1 release. Nevertheless, bMEC were able to release neutrophil-mobilizing chemokines and pro-inflammatory cytokines upon bacterial stimulation, strongly suggesting that bMEC are active contributors to immune and inflammatory responses of mammary gland. In addition, the clinical characteristics and resolution of mastitis may be partly determined by the responses of bMEC according to S. aureus strains and bacteria Gram type.

Gut responses to enteral nutrition in preterm infants and animals

Preterm birth is associated with immature digestive function that may require the use of total parenteral nutrition and special oral feeding regimens. Little is known about the responses to oral food in the preterm neonate and how enteral nutrients affect the immature gastrointestinal tract (GIT). In vivo studies are difficult to perform in laboratory rodents because of their small body size and that of immature organs at birth, and this makes the large farm animals (e.g., pigs, cattle, sheep) more attractive models in this field. In these species, preterm delivery at 88%-95% gestation is associated clinical complications and degrees of GIT immaturity similar to those in infants born at 70%-90% gestation. Studies in both animals and infants indicate that the immature GIT responds to the first enteral food with rapid increases in gut mass and surface area, blood flow, motility, digestive capacity, and nutrient absorption. To a large extent, the enteral food responses are birth independent, and can be elicited also in utero, at least during late gestation. Nevertheless, preterm neonates show compromised GIT structure, function, and immunology, particularly when delivered by caesarean section and fed diets other than mother's milk. Formula-fed preterm infants are thus at increased risk of developing diseases such as necrotizing enterocolitis, unless special care is taken to avoid excessive nutrient fermentation and bacterial overgrowth. The extent to which results obtained in preterm animals (most notably the pig) can be used to reflect similar conditions in preterm infants is discussed.

Neutrophil-specific chemokines are produced by astrocytic cells but not by neuronal cells

BACKGROUND

Neutrophils have a central role in the inflammatory conditions of the central nervous system (CNS). ELR chemokines direct neutrophil migration, but the source of chemokines in the CNS is unclear. We quantified chemokine production using cell-line models of astrocytic and neuronal cells, specifically NT2.N cells, a human line with characteristics of immature neurons, and NT2.A cells, a line with characteristics of astrocytes.

OBJECTIVE

In NT2.N and NT2.A cells, and their parent cell line NT2, we sought to: (1) quantify ELR chemokines, (2) determine receptor (CXCR-1 and CXCR-2) expression, and (3) measure the function of the chemokines generated from these cells.

DESIGN/METHODS

NT2 cells were differentiated into NT2.N cells and NT2.A cells with all trans retinoic acid and mitosis inhibitors. Chemokine concentrations in culture supernatants were determined by ELISA. Immunofluorescence was used to detect CXCR-1 and CXCR-2. RT-PCR was used to determine chemokine and chemokine receptor mRNA. Chemotaxis assays were used to assess function.

RESULTS

ELR chemokines were not detected in supernatants of NT2 or NT2.N cells, although mRNA for GRO-gamma/CXCL3 was found in both. In contrast, in NT2.A cells, mRNA and protein were present for GCP-2/CXCL6, GRO-alpha/CXCL1, GRO-gamma/CXCL3, and IL-8/CXCL8. CXCR-1 and CXCR-2 were expressed on NT2, NT2.N, and NT2.A cells detected by immunofluorescent staining and RT-PCR. Supernatants of NT2.A cells resulted in neutrophil chemotactic function of 30.5 +/- 3.9%, greater than NT2 cells (12.3 +/- 1.6%, mean +/- SEM, P < 0.01).

CONCLUSIONS

We speculate that astrocytes are a source of ELR chemokines in the human CNS and that neurons and astrocytes can respond to those chemokines.

IL-8/CXC ligand 8 survives neonatal gastric digestion as a result of intrinsic aspartyl proteinase resistance

The human fetus and neonate swallow biologically significant quantities of IL-8/CXC ligand 8 (CXCL8) in amniotic fluid and breast milk, and this remains measurable through simulated neonatal gastric and proximal intestinal digestions. We sought to confirm the structural and functional integrity of IL-8/CXCL8 in digestates and determine the mechanisms underlying this protease resistance. We observed that in comparison with BSA, IL-8/CXCL8 is highly resistant to pepsin and can be detected intact in assays for structural, immunologic, and functional integrity. In a computational molecular docking simulation, IL-8/CXCL8 was observed to fit poorly in the pepsin active site. On the basis of simulated mutation analyses, we hypothesized that this protease resistance is due to disulfide bond-related tertiary folding in IL-8/CXCL8. This was confirmed on chemical reduction of these groups.

Interleukin-8/CXCL8 forms an autocrine loop in fetal intestinal mucosa

IL-8/CXC ligand (CXCL) 8 is ingested in high concentrations by the human fetus/neonate with amniotic fluid and human milk, and is also produced constitutively by intestinal epithelial cells (IEC). We have shown that recombinant human IL-8/CXCL8 (rhIL-8/CXCL8) protects cultured IEC against tumor necrosis factor (TNF)-alpha and cycloheximide-induced cytotoxicity. In view of its constitutive production, we hypothesized that IL-8/CXCL8 might play an autocrine role in fetal enterocyte maintenance. In this study, we measured IL-8/CXCL8 mRNA concentrations in fetal intestine (11-22 wk gestation), sought the presence of the protein by immunohistochemistry in fetal stomach and intestine (9-24 wk), measured IL-8/CXCL8 in neonatal gastric secretions, and studied constitutive and stimulated IL-8/CXCL8 expression in cultured IEC. We found that IL-8/CXCL8 is consistently transcribed and expressed in fetal intestinal tissue, in a developmentally regulated inverse relationship with gestational maturation. The cognate receptors for IL-8/CXCL8 are also expressed abundantly in the fetal intestine, and, therefore, we sought to determine whether the expressed IL-8/CXCL8 would complete an autocrine loop. Neutralization of IL-8/CXCL8 resulted in increased cell death in cultured IEC in the presence of TNF-alpha. This effect is specifically mediated through the CXCR2 receptors. We speculate that IL-8/CXCL8 secretion during cytotoxic stress reflects a cellular self-defense mechanism.