Differential expression and secretion of bovine serum amyloid A3 (SAA3) by mammary epithelial cells stimulated with prolactin or lipopolysaccharide

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.

Peptidomic changes in the milk of water buffaloes (Bubalus bubalis) with intramammary infection by non-aureus staphylococci

Mastitis by non-aureus staphylococci (NAS) is a significant issue in dairy buffalo farming. In a herd with subclinical NAS mastitis, we identified Staphylococcus microti as the predominant species. To assess milk protein integrity and investigate potential disease markers, we characterized 12 NAS-positive and 12 healthy quarter milk samples by shotgun peptidomics combining peptide enrichment and high-performance liquid chromatography/tandem mass spectrometry (LC–MS/MS). We observed significant changes in the milk peptidome. Out of 789 total peptides identified in each group, 49 and 44 were unique or increased in NAS-positive and healthy milk, respectively. In NAS-positive milk, the differential peptides belonged mainly to caseins, followed by milk fat globule membrane proteins (MFGMP) and by the immune defense/antimicrobial proteins osteopontin, lactoperoxidase, and serum amyloid A. In healthy milk, these belonged mainly to MFGMP, followed by caseins. In terms of abundance, peptides from MFGMP and immune defense protein were higher in NAS-positive milk, while peptides from caseins were higher in healthy milk. These findings highlight the impact of NAS on buffalo milk quality and mammary gland health, even when clinical signs are not evident, and underscore the need for clarifying the epidemiology and relevance of the different NAS species in this dairy ruminant.

Milk proteins as mastitis markers in dairy ruminants - a systematic review

Mastitis is one of the most impacting diseases in dairy farming, and its sensitive and specific detection is therefore of the greatest importance. The clinical evaluation of udder and mammary secretions is typically combined with the milk Somatic Cell Count (SCC) and often accompanied by its bacteriological culture to identify the causative microorganism. In a constant search for improvement, several non-enzymatic milk proteins, including milk amyloid A (M-SAA), haptoglobin (HP), cathelicidin (CATH), and lactoferrin (LF), have been investigated as alternative biomarkers of mastitis for their relationship with mammary gland inflammation, and immunoassay techniques have been developed for detection with varying degrees of success. To provide a general overview of their implementation in the different dairy species, we carried out a systematic review of the scientific literature using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. Our review question falls within the type “Diagnostic test accuracy questions” and aims at answering the diagnostic question: “Which are the diagnostic performances of mastitis protein biomarkers investigated by immunoassays in ruminant milk?”. Based on 13 keywords combined into 42 searches, 523 manuscripts were extracted from three scientific databases. Of these, 33 passed the duplicate removal, title, abstract, and full-text screening for conformity to the review question and document type: 78.8% investigated cows, 12.1% sheep, 9.1% goats, and 6.1% buffaloes (some included more than one dairy species). The most frequently mentioned protein was M-SAA (48.5%), followed by HP (27.3%), CATH (24.2%) and LF (21.2%). However, the large amount of heterogeneity among studies in terms of animal selection criteria (45.5%), index test (87.9%), and standard reference test (27.3%) resulted in a collection of data not amenable to meta-analysis, a common finding illustrating how important it is for case definitions and other criteria to be standardized between studies. Therefore, results are presented according to the SWiM (Synthesis Without Meta-analysis) guidelines. We summarize the main findings reported in the 33 selected articles for the different markers and report their results in form of comparative tables including sample selection criteria, marker values, and diagnostic performances, where available. Finally, we report the study limitations and bias assessment findings.

Induction of Serum Amyloid A3 in Mouse Mammary Epithelial Cells Stimulated with Lipopolysaccharide and Lipoteichoic Acid

Simple Summary

Serum amyloid A (SAA) is an acute phase protein present in mammals and birds. Based on the amino acid sequence, SAA has been classified into isoforms SAA1–4 in mice. Previously, it was reported that after the stimulation with bacterial antigens, the expression of the Saa3 mRNA was induced more strongly than that of the Saa1 mRNA in mouse epithelia, including colonic and alveolar epithelial cells, indicating that SAA3 plays a role in the local response. However, the contribution of SAA3 to the local response in mouse mammary epithelium, where mastitis occurs due to bacterial infection, has not been completely determined yet. In this study, to clarify whether mouse SAA3 has a role in the defense against bacterial infection in mouse mammary epithelium, normal murine mammary gland (NMuMG) epithelial cells were stimulated with lipopolysaccharide (LPS) and lipoteichoic acid (LTA). LPS and LTA significantly enhanced mRNA expression level of the Saa3 gene but not that of Saa1. Furthermore, LPS induced SAA3 protein expression more strongly than LTA. Our data indicate that SAA3 expression in mouse mammary epithelial cells was increased by the stimulation with bacterial antigens, suggesting that SAA3 is involved in the defense against bacterial infection in mouse mammary epithelium.

Abstract

In this study, to establish whether serum amyloid A (SAA) 3 plays a role in the defense against bacterial infection in mouse mammary epithelium, normal murine mammary gland (NMuMG) epithelial cells were stimulated with lipopolysaccharide (LPS) and lipoteichoic acid (LTA). LPS and LTA significantly enhanced mRNA expression level of the Saa3 gene, whereas no significant change was observed in the Saa1 mRNA level. Furthermore, LPS induced SAA3 protein expression more strongly than LTA, whereas neither LPS nor LTA significantly affected SAA1 protein expression. These data indicate that the expression of SAA3 in mouse mammary epithelial cells was increased by the stimulation with bacterial antigens. SAA3 has been reported to stimulate neutrophils in the intestinal epithelium and increase interleukin-22 expression, which induces activation of the innate immune system and production of antibacterial proteins, such as antimicrobial peptides. Therefore, collectively, these data suggest that SAA3 is involved in the defense against bacterial infection in mouse mammary epithelium.

Investigation of acute-phase proteins and cytokines response in goats with contagious caprine pleuropneumonia with special reference to their diagnostic accuracy

Acute-phase proteins (APPs) have always had valued diagnostic potentialities in response to infection. This study aimed to evaluate the diagnostic accuracy of selected APPs and proinflammatory cytokines (PIC) in goats with contagious caprine pleuropneumonia (CCPP) under field conditions. Moreover, to highlight the role of tested biomarkers in CCPP pathogenesis. Fifty-eight goats (38 confirmed cases with CCPP and 20 healthy controls) were involved in this investigation. C-reactive protein (CRP), procalcitonin (PCT), haptoglobin (HP), fibrinogen (Fb), serum amyloid A (SAA), selected PIC (IL1-α, IL1-β, IL-6, interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α)) levels were investigated in serum samples from all goats under investigation. Latex agglutination test was used for diagnosis of goats with CCPP. For microbiological investigations, nasopharyngeal swabs (from all goats), lung tissues and pleural fluids (from only necropsied goats) were collected. This study revealed that all tested parameters have a high to moderate degree of diagnostic performance for CCPP. Magnitudes of increase in levels of APPs (CRP, HP and SAA) were stronger than PIC, IFN-γ, Fb and PCT. All tested parameters showed high diagnostic accuracy (AUROC >90%), except HP (AUROC = 87.3%) and IFN-γ (AUROC = 78.8%) showed moderate accuracy in differentiation of goats with and without CCPP infection. For detecting goats with and without CCPP infection, HP had the lowest sensitivity (Se = 81.6%) and Fb had the lowest specificity (Sp = 85.0%) among the APPs parameters tested. However, PCT showed the highest Se (100%) and Sp (95.0%) to detect goats with and without CCPP infection among tested parameters. Conclusively, this study endorses the significance of selected APPs and PIC as additional screening diagnostic parameters for naturally occurring CCPP in goats. However, it does not replace traditional methods for diagnosis of CCPP in goats. Furthermore, APPs and PIC have an important role in disease pathogenesis in goats.

Changes in blood biomarkers in Arabian horses with Clostridium difficile-induced enterocolitis

Clostridium difficile (CD) is considered a major health care problem both in developing and developed countries; frequently reported to be associated with enterocolitis and diarrhea in horses and other animals. In this study, we examined acute phase response (APR), cytokines response, neopterin (NP) procalcitonin (PCT) production and oxidative stress condition in horses and foals with C. difficile-induced enterocolitis (CDIE) and evaluated the effectiveness of these parameters as biomarkers for the disease. A total of 407 Arabian horses in 35 stables were examined between January 2017 to December 2018. Only 24 out of 407 horses showed two or more signs of CDIE. The blood level of serum amyloid A (SAA), haptoglobin (HP), proinflammatory cytokines (TNF-α, IL-6 and IL1-β), serum malondialdehyde (MDA), PCT and NPT in horses with CDIE were higher than in healthy horses. Nevertheless, the levels of nitric oxide (NO), superoxide dismutase (SOD) and total antioxidant concentration (TAC) were considerably lower in diseased horses compared to those that were healthy. The ROC curves for eleven selected blood parameters, both in healthy horses and horses with CDIE demonstrated that all examined blood markers had significant levels of differentiation between CDIE cases and healthy controls (AUC > 87.5). The data in this study suggest that the evaluation of acute-phase proteins, cytokines, PCT, NPT, and oxidative stress biomarkers may well be used as a tool for diagnosis and assessment of CDIE and in disease pathogenesis in Arabian horses.

Sequential changes in hepatic mRNA abundance and serum concentration of serum amyloid A in cattle with acute inflammation caused by endotoxin

The objective of the present study was to elucidate sequential changes in mRNA abundance of serum amyloid A (SAA) isotypes in endotoxin (ETX) challenge model cattle. Ten healthy cattle were separated to 2 groups: control and ETX groups. Cattle in the ETX group were challenged by 2.5 µg/kg of O111:B4 lipopolysaccharide in 4 ml of autologous serum. Blood samples were withdrawn at pre, 0.5, 1, 2, 4, 8, 12, 24, 48, 72 and 96 hr after ETX challenge. Plasma ETX activity, serum SAA concentrations, mRNA abundance of interleukin (IL)-6, SAA2 and SAA4 in the liver and polymorphonuclear leukocytes were measured. The plasma ETX activity in the ETX group increased at 0.5 hr after the ETX challenge. The serum SAA value remained higher between 12 and 72 hr after the ETX challenge than that of the control group. Hepatic IL-6 mRNA abundance in the ETX group increased at 2 hr after the ETX challenge. Hepatic SAA2 and SAA4 mRNA abundance significantly increased from 4 hr after administration, and remained significantly higher than those pre-values up to 12 and 24 hr, respectively. The abundance ratio of hepatic SAA2 was much higher than that of SAA4. The major isotype was SAA2 in liver tissue, and it is indicating systemic inflammation in cattle.

Differential expression of serum amyloid A1 and A3 in bovine epithelia

Serum amyloid A (SAA) is both an amyloidogenic protein of amyloid A amyloidosis and an acute phase protein in most animal species. Although SAA isoforms, such as SAA1, 2, 3, and 4, have been identified in cattle, their biological functions are not completely understood. Previous studies using mice indicated that SAA3 mRNA expression increased by stimulation with Escherichia coli and lipopolysaccharide (LPS) in colonic epithelial cells, and subsequently the SAA3 protein enhanced the expression of mucin2 (MUC2) mRNA, which is the major component of the colonic mucus layer. These results suggest that SAA3 plays a role in host innate immunity against bacterial infection in the intestine. In this study, a novel anti-bovine SAA3 monoclonal antibody was produced and SAA3 expression levels in bovine epithelia were examined in vitro and in vivo using real-time PCR and immunohistochemistry (IHC). SAA3 mRNA expression, but not that of SAA1, was enhanced by LPS stimulus in bovine small intestinal and mammary glandular epithelial cells in vitro. Moreover, in bovine epithelia (small intestine, mammary gland, lung, and uterus) obtained from four Holstein dairy cows from a slaughterhouse, SAA3 mRNA expression was higher than that of SAA1. Furthermore, using IHC, SAA3 protein expression was observed in bovine epithelia, whereas SAA1 protein was not. These results suggest that in cattle, SAA3 plays an immunological role against bacterial infection in epithelial tissues, including the small intestine, mammary gland, lung, and uterus.

Use of procalcitonin, neopterin, haptoglobin, serum amyloid A and proinflammatory cytokines in diagnosis and prognosis of bovine respiratory disease in feedlot calves under field conditions

Bovine respiratory diseases (BRD) have long been considered a serious problem that causes major economic losses in feedlot calves (FC). This study aimed to determine the diagnostic and prognostic effect of selected biological markers including, procalcitonin (PCT), neopterin (NP), proinflammatory cytokines (IL-1β, IL-8, TNF-α, IF-γ), haptoglobin (HP) and serum amyloid A (SAA) on FC with BRD under field conditions. Sixty-nine FC that were identified to be infected with Mannheimia haemolytica and Histophilus somni and had different clinical respiratory signs (diseased group) were selected for this study. In addition, 20 healthy FC have been selected as a control group. We have detected higher serum levels of PCT, NP, HP, SAA, IL-1β, IL-8, TNF-α and IF-γ in diseased FC group compared with the control group. All tested markers revealed a high level of discrimination between BRD infected FC and healthy ones (AUC > 0.90). Moreover, the obtained data showed a high degree of prognostic accuracy for PCT, NP, IL-8, HP, IF-γ and IL-1β in predicting treatment response of FC with BRD at the selected thresholds (AUC = 0.99, 0.99, 0.97, 0.93, 0.88 and 0.82, respectively). Significant inhibition was observed for the selected biochemical markers in treated FC 7 days post-treatment. In conclusion, this study showed that BRD in FC was associated with significant alterations in serum APPs, proinflammatory cytokines, PCT and NPT levels. Furthermore, it demonstrated that these serum biomarkers are much higher in FC with BRD compared to recovered ones. Our data suggest that the measurement of PCT, NPT, APPs and cytokines together with the clinical examination may be a useful diagnostic and prognostic tool for assessment of FC naturally infected with M. haemolytica and H. somni.

Serum Amyloid A (SAA) Proteins

As normal constituents of blood serum, the Serum Amyloid A (SAA) proteins are small (104 amino acids in humans) and remarkably well-conserved in mammalian evolution. They are synthesized prominently, but not exclusively, in the liver. Fragments of SAA can associate into insoluble fibrils (called "amyloid") characteristic of "secondary" amyloid disease in which they can interrupt normal physiology and lead to organ failure. SAA proteins comprise a family of molecules, two members of which (SAA1 and SAA2) are (along with C-reactive protein, CRP) the most prominent members of the acute phase response (APR) during which their serum levels rise dramatically after trauma, infection and other stimuli. Biologic function (s) of SAA are unresolved but features are consistent with a prominent role in primordial host defense (including the APR ). SAA proteins are lipophilic and contribute to high density lipoproteins (HDL) and cholesterol transport. SAA proteins interact with specific receptors and have been implicated in tissue remodeling through metalloproteinases, local tissue changes in atherosclerosis, cancer metastasis, lung inflammation, maternal-fetal health and intestinal physiology. Molecular details of some of these are emerging.

Serum amyloid A - a review

Serum amyloid A (SAA) proteins were isolated and named over 50 years ago. They are small (104 amino acids) and have a striking relationship to the acute phase response with serum levels rising as much as 1000-fold in 24 hours. SAA proteins are encoded in a family of closely-related genes and have been remarkably conserved throughout vertebrate evolution. Amino-terminal fragments of SAA can form highly organized, insoluble fibrils that accumulate in “secondary” amyloid disease. Despite their evolutionary preservation and dynamic synthesis pattern SAA proteins have lacked well-defined physiologic roles. However, considering an array of many, often unrelated, reports now permits a more coordinated perspective. Protein studies have elucidated basic SAA structure and fibril formation. Appreciating SAA’s lipophilicity helps relate it to lipid transport and metabolism as well as atherosclerosis. SAA’s function as a cytokine-like protein has become recognized in cell-cell communication as well as feedback in inflammatory, immunologic, neoplastic and protective pathways. SAA likely has a critical role in control and possibly propagation of the primordial acute phase response. Appreciating the many cellular and molecular interactions for SAA suggests possibilities for improved understanding of pathophysiology as well as treatment and disease prevention.

Serum amyloid A1 (SAA1) protein in human colostrum

Proteins of the serum amyloid A (SAA) family have been remarkably conserved in evolution. Their biologic function(s) are not fully defined but they are likely to be a part of primordial host defense. We have detected a ∼ 12‐kDa protein reacting with antibodies against serum amyloid A (SAA) in human colostrum by western blotting. Mass spectrometry identified the reactive species as SAA1, previously identified as a prominent member of the acute‐phase response in serum. Our finding SAA1 in human colostrum contrasts with bovine, caprine and ovine colostrum where a species corresponding to putative SAA3 is uniformly present. SAA1 protein in human colostrum presumably contributes to neonatal protection.

Milk amyloid A as a biomarker for diagnosis of subclinical mastitis in cattle

Background and Aim

Mastitis is one of the most vital noteworthy monetary risks to dairy ranchers and affects reproductive performance in dairy cattle. However, subclinical mastitis (SCM) negatively affects milk quality and quantity and associated with economic losses as clinical mastitis. It is recognizable only by additional testing. Somatic cell count (SCC) is currently used worldwide for the screening of intramammary infection (IMI) infections. However, somatic cells (SC) are affected by numerous factors and not always correlate with infection of the udder. Therefore, the aim of the present study was to evaluate the milk amyloid A (MAA) in the milk of normal and SCM cows and compare the sensitivity of both MAA secretion and SCC in response to mammary gland bacterial infection.

Materials and Methods

A total of 272 quarter milk samples collected from 68 Friesian cows after clinical examination for detection of clinical mastitis were employed in this study. All quarter milk samples (272) were subjected to bacteriological examination, while SCs were assessed in samples (220). Following SCC estimation and bacteriological examination, the apparently normal quarter milk samples were categorized into 7 groups and MAA concentration was estimated in normal and subclinical mastitic milk samples.

Results

Prevalence of clinical mastitis was 19.12 % (52 quarters), while 80.88 % (220 quarters) were clinically healthy with normal milk secretion. Of those 220 clinically healthy quarter milk samples, 72 (32.73%) showed SCM as detected by SCC (SCC ≥500,000 cells/ml). The most prevalent bacteria detected in this study were streptococci (48.53%), Staphylococcus aureus (29.41%), Escherichia coli (36.76%), and coagulase-negative staphylococci (11.76%). Results of MAA estimation revealed a strong correlation between MAA secretion level and SCC in agreement with the bacteriological examination. Interestingly, there was a prompt increase in MAA concentration in Group III (G III) (group of milk samples had SCC ≤200,000 cells/ml and bacteriologically positive) than Group I (G I) (group of milk samples with SCC ≤500,000 cells/ml and bacteriologically negative), as MAA concentration in G III was about 4 times its concentration in G I.

Conclusion

Our study provides a strong evidence for the significance of MAA measurement in milk during SCM, and MAA is more sensitive to IMI than SCC. This can be attributed to rapid and sensitive marker of inflammation. The advantage of MAA over other diagnostic markers of SCM is attributed the minute or even undetectable level of MAA in the milk of healthy animals, it is not influenced by factors other than mastitis, and could be estimated in preserved samples. Therefore, we recommend that estimation of MAA concentration in milk is a more useful diagnostic tool than SCC to detect SCM and to monitor the udder health in dairy cattle.

Haptoglobin and serum amyloid A as putative biomarker candidates of naturally occurring bovine respiratory disease in dairy calves

Bovine respiratory disease (BRD) is one of the leading causes of morbidity and mortality in dairy calves. Identification of reliable biomarkers of naturally occurring BRD is essential for ensuring early diagnosis and treatment of calves and monitoring treatment efficacy. This need is punctuated, especially in mild to moderate cases that would greatly help to decrease recurrence and the overall prevalence of BRD. The present study was conducted to investigate the changes in serum concentrations of haptoglobin (Hpt) and serum amyloid A (SAA) and association between oxidative stress and acute phase proteins (APPs) in BRD. Hpt and SAA levels significantly increased (P < .01) in BRD stressed calves as compared to healthy subjects. There was a significant decrease (P < .01) in serum albumin (Alb) concentration of infected calves as compared to controls. The oxidative stress markers revealed a significant (P < .01) increase in lipid peroxidation (LPO) and a concurrent decrease in activities of superoxide dismutase (SOD), reduced glutathione (R-GSH) and catalase (CAT) in BRD. A significant correlation among APPs, extent of oxidative stress and clinical score (CS) of calves was depicted. A stepwise decrease in Hpt and SAA and increase in Alb was observed in infected calves post-treatment. These results suggest implication of oxidative stress in enhancing APPs and monitoring of APPs as a potential complement to clinical assessment of treatment in calves with naturally occurring BRD. Hpt may be useful as the most sensitive biomarker in BRD. However, the combined use of Hpt and oxidative stress biomarkers would greatly improve the diagnostic accuracy.

The Pig PeptideAtlas: A resource for systems biology in animal production and biomedicine

Biological research of Sus scrofa, the domestic pig, is of immediate relevance for food production sciences, and for developing pig as a model organism for human biomedical research. Publicly available data repositories play a fundamental role for all biological sciences, and protein data repositories are in particular essential for the successful development of new proteomic methods. Cumulative proteome data repositories, including the PeptideAtlas, provide the means for targeted proteomics, system-wide observations, and cross-species observational studies, but pigs have so far been underrepresented in existing repositories. We here present a significantly improved build of the Pig PeptideAtlas, which includes pig proteome data from 25 tissues and three body fluid types mapped to 7139 canonical proteins. The content of the Pig PeptideAtlas reflects actively ongoing research within the veterinary proteomics domain, and this article demonstrates how the expression of isoform-unique peptides can be observed across distinct tissues and body fluids. The Pig PeptideAtlas is a unique resource for use in animal proteome research, particularly biomarker discovery and for preliminary design of SRM assays, which are equally important for progress in research that supports farm animal production and veterinary health, as for developing pig models with relevance to human health research.

The diagnostic accuracy of acute phase proteins and proinflammatory cytokines in sheep with pneumonic pasteurellosis

The goal of this study was to assess the diagnostic accuracy of acute phase proteins and proinflammatory cytokines in sheep with pneumonic pasteurellosis. Blood samples were collected from 56 sheep (36 naturally infected with Pasteurella multocida and 20 healthy controls) belonging to one farm in Eastern region, Saudi Arabia. Serum samples were evaluated for acute phase proteins (Haptoglobin (Hp), serum amyloid A (SAA) and fibrinogen (Fb)), and the proinflammatory cytokines (interleukins (IL-1α, IL-1β, and IL-6), tumor necrosis factor-alpha (TNF-α), and interferon-gamma (IFN-ϒ)). Additionally, nasopharyngeal swabs and bronchoalveolar lavages were collected from all animals for bacteriological examinations. Receiver operating characteristic curve was used to assess the diagnostic performance of each parameter. All parameters showed moderate to high degree of positive correlation with case-control status. There was no significant difference in the area under the curve (AUC) among acute phase proteins; however, both Hp and SAA showed better sensitivity and specificity than Fb. The proinflammatory cytokines (IL1-α, IL1-β, and IL6) showed similar and highly accurate diagnostic performance (AUC > 0.9), whereas IFN-ϒ was moderately accurate (AUC = 0.79). In conclusion, this study confirms the value of acute phase proteins and cytokines as diagnostic biomarkers of naturally occuring pneumonic pasteurellosis in sheep.

Continuous evaluation of changes in the serum proteome from early to late stages of sepsis caused by Klebsiella pneumoniae

Serum protein profiles of patients with bacterial sepsis from the day of diagnosis until recovery/mortality were compared from early to late stages in response to severe sepsis using two dimensional electrophoresis. The proteins exhibiting changes during the course of sepsis (20‑28 day mortality) were selected and identified by matrix‑assisted laser desorption ionization‑time of flight‑tandem mass spectrometry. Among the proteins identified, haptoglobin (Hp), transthyretin (TTR), orosomucoid 1/α1 acid glycoprotein (ORM1), α1 antitrypsin (A1AT), serum amyloid A (SAA) and S100A9 exhibited differential expression patterns between survivors (S; n=6) and non‑survivors (NS; n=6), particularly during the early stages of sepsis. Expression factors (EFs), taken as the ratio between the NS and S during early stages, showed ratios of Hp, 0.39 (P≤0.012); TTR, 3.96 (P≤0.03); ORM1, 0.69 (P≤0.79); A1AT, 0.92 (P≤0.87) and SAA, 0.69 (P≤0.01). S100A9, an acute phase protein, exhibited an EF ratio of 1.68 (P≤0.004) during the end stages of sepsis. A delayed rise in levels was observed in Hp, A1AT, ORM1, S100A9 and SAA, whereas TTR levels increased during the early stages of sepsis in NS. Analysis of inflammatory responses in the early stages of sepsis revealed increased mRNA expression in leukocytes of interleukin (IL)‑6 (EF, 2.50), IL‑10 (EF, 1.70) and prepronociceptin (EF, 1.6), which is a precursor for nociceptin in NS compared with S, and higher Toll‑like receptor‑4 (EF, 0.30) levels in S compared with NS. Therefore, a weaker acute phase response in the early stages of sepsis in NS, combined with an inefficient inflammatory response, may contribute to sepsis mortality.

Transcriptional profiling of mammary gland in Holstein cows with extremely different milk protein and fat percentage using RNA sequencing

Background

Recently, RNA sequencing (RNA-seq) has rapidly emerged as a major transcriptome profiling system. Elucidation of the bovine mammary gland transcriptome by RNA-seq is essential for identifying candidate genes that contribute to milk composition traits in dairy cattle.

Results

We used massive, parallel, high-throughput, RNA-seq to generate the bovine transcriptome from the mammary glands of four lactating Holstein cows with extremely high and low phenotypic values of milk protein and fat percentage. In total, we obtained 48,967,376–75,572,578 uniquely mapped reads that covered 82.25% of the current annotated transcripts, which represented 15549 mRNA transcripts, across all the four mammary gland samples. Among them, 31 differentially expressed genes (p < 0.05, false discovery rate q < 0.05) between the high and low groups of cows were revealed. Gene ontology and pathway analysis demonstrated that the 31 differently expressed genes were enriched in specific biological processes with regard to protein metabolism, fat metabolism, and mammary gland development (p < 0.05). Integrated analysis of differential gene expression, previously reported quantitative trait loci, and genome-wide association studies indicated that TRIB3, SAA (SAA1, SAA3, and M-SAA3.2), VEGFA, PTHLH, and RPL23A were the most promising candidate genes affecting milk protein and fat percentage.

Conclusions

This study investigated the complexity of the mammary gland transcriptome in dairy cattle using RNA-seq. Integrated analysis of differential gene expression and the reported quantitative trait loci and genome-wide association study data permitted the identification of candidate key genes for milk composition traits.

Epigenetic contribution to individual variation in response to lipopolysaccharide in bovine dermal fibroblasts

The innate immune signaling pathway plays a crucial role in the recognition and early response to pathogens associated with disease. Genetic analysis has been unable to completely account for individual variability in the strength of the innate immune response. The aim of this study was to determine the role of the epigenetic markers (DNA methylation or histone acetylation) in controlling bovine gene expression in relation to the response to lipopolysaccharide (LPS). To determine the impact epigenetics may have in controlling innate immunity, dermal fibroblasts from fifteen dairy heifers having previously displayed a differential response to LPS were exposed to 5-aza-2'-deoxycytidine (AZA) and trichostatin A (TSA); de-methylating and hyper-acetylating agents, respectively. The AZA-TSA exposure resulted in a loss of variability between individuals' response to LPS as measured by fibroblast IL-8 protein production. Transcriptomic analysis by microarray was used to elucidate the role of epigenetics in innate immune signaling at 2, 4, and 8h post-LPS exposure. A subset of genes displayed altered expression due to AZA-TSA alone, suggesting an epigenetic regulatory element modifying expression under normal conditions. Treatment with AZA-TSA also led to increased expression of IL-8 (7.0-fold), IL-6 (2.5-fold), TNF-α (1.6-fold), and serum amyloid A 3 (SAA3) (11.3-fold) among other genes compared to control cultures for at least one of the measured times following LPS exposure. These data support the conclusion that epigenetic regulation significantly alters LPS-induced responses and constitutive cytokine gene expression.

Use of milk amyloid A in the diagnosis of subclinical mastitis in dairy ewes

Subclinical mastitis (SM) is one of the most important diseases affecting dairy ewes worldwide, with negative impact on the animal health, farm income and public health. Animals with SM often remain untreated because the disease may not be revealed. Increase in somatic cell count (SCC) and positive bacteriology for mastitis pathogens in milk samples are indicative of SM but the evidence of only one of these alterations must suggest an uncertain SM (UM). UM is defined when positive bacteriological examination (Latent-SM) or SCC>500 000 cells/ml (non-specific-SM) are detected in milk. Nevertheless, SCC and bacteriological examination are expensive, time consuming and are not yet in use at the farm level in dairy ewes. Recently, a sensitive acute phase protein, amyloid A, displaying multiple isoforms in plasma and different body fluids including mammary secretion (milk amyloid A-MAA), has been investigated as a marker of mastitis in cows and, in a few studies, in sheep. The aim of this trial was to compare the concentration of MAA of single udder-halves in ewes with healthy udder-halves (HU-control group) and naturally occurring subclinical mastitis, both confirmed (SM group) and uncertain (UM groups: Latent-SM and non-specific-SM), for monitoring udder health. The reliability of a specific ELISA kit for the measurement of MAA was also tested. During a 3-month trial period, 153 udder halves were assigned to the experimental groups based on their health status: 25 with SM, 40 with UM (11 with latent-SM and 29 with non-specific-SM) and 88 HU. SCC and bacteriological analysis were performed to establish the control and subclinical mastitis groups. MAA concentrations in milk samples were measured using a specific commercially milk ELISA kit. The data were submitted to statistical analysis. Significant (P<0·05) differences among the groups SM, non-specific-SM and HU were detected with the SM having the highest level and HU the lowest. MAA concentration is affected by the udder health status and is a useful indicator of subclinical mastitis and increased SCC in sheep.

Enzyme activity and acute phase proteins in milk utilized as indicators of acute clinical E. coli LPS-induced mastitis

The importance of non-visual and on-line monitoring of udder health increases as the contact between humans and animals decreases, for example, in robotic milking systems. Several indicator systems have been introduced commercially, and a number of techniques are currently in use. This study describes the kinetics of seven indigenous milk parameters for monitoring udder inflammation in an Escherichia coli lipopolysaccharide (LPS, endotoxin)-induced mastitis model. Proportional milk from LPS-infused quarters was compared with milk from parallel quarters, which were placebo-treated with sterile 0.9% NaCl solution. Somatic cell counts (SCCs), the acute phase proteins (APP), that is, milk amyloid A (MAA) and haptoglobin (Hp), and the enzymes N-acetyl-β-D-glucosaminidase (NAGase), lactate dehydrogenase (LDH), alkaline phosphatase (AP) and acid phosphatase (AcP) were measured at fixed intervals during the period from -2 to +5 days after LPS and NaCl infusions. All parameters responded significantly faster and were more pronounced to the LPS infusions compared with the NaCl infusions. All parameters were elevated in the proportional milk collected at the first milking 7 h after infusion and developed a monophasic response, except Hp and MAA that developed biphasic response. SCC, LDH, NAGase and Hp peaked at 21 h followed by AP, AcP and MAA peaking at 31 h with the highest fold changes seen for MAA (23 780×), LDH (126×), NAGase (50×) and Hp (16×). In the recovery phase, AP, AcP and Hp reached base levels first, at 117 h, whereas LDH, NAGase and MAA remained elevated following the pattern of SCC. Minor increases of the milk parameters were also seen in the neighboring (healthy) quarters. Distinction between inflamed and healthy quarters was possible for all the parameters, but only for a limited time frame for AP and AcP. Hence, when tested in an LPS mastitis model, the enzymes LDH, NAGase and AP in several aspects performed equally with SCC and APP as inflammatory milk indicators of mastitis. Furthermore, these enzymes appear potent in the assessment of a valuable time sequence of inflammation, a necessary ingredient in modeling of programs in in-line surveillance systems.

Validation of RNA isolated from milk fat globules to profile mammary epithelial cell expression during lactation and transcriptional response to a bacterial infection

Mastitis, an inflammation of the mammary gland, is the most costly infectious disease of dairy ruminants worldwide. Although it receives considerable attention, the early steps of the host response remain poorly defined. Here, we report a noninvasive method using milk fat globules (MFG) as a source of mammary RNA to follow the dynamics of the global transcriptional response of mammary epithelial cells (MEC) during the course of a bacterial infection. We first assessed that RNA isolated from MFG were representative of MEC RNA; we then evaluated whether MFG RNA could be used to monitor the MEC response to infection. Sufficiently high yields of good-quality RNA (RNA integrity numbers ranging between 6.7 and 8.7) were obtained from goat MFG for subsequent analyses. Contamination of MFG by macrophages and neutrophils, which can be trapped during creaming, was assessed and when using quantitative real-time PCR for cell-type specific markers, was shown to be weak enough (<8%) to affect MFG gene expression profiling. Using microarrays, we showed that RNA extracted from MFG and from mammary alveolar parenchyma shared approximately 90% of the highlighted probes corresponding in particular to genes encoding milk proteins (CSN, BLG, LALBA) and enzymes involved in milk fat synthesis and secretion (FASN, XDH, ADRP, SCD, and DGAT1). In addition, a gene involved in the acute-phase reaction, coding for the serum amyloid A3 (SAA3) protein, was found within the first 50 most highly expressed genes in a noninfectious context in both mammary alveolar parenchyma and MFG, strongly suggesting that SAA3 is expressed in MEC. We took advantage of this noninvasive RNA sampling to follow the early proinflammatory response of MEC during the course of a bacterial infection and showed that the levels of mRNA encoding SAA3 sharply increased at 24h postinfection. Taken together, our results demonstrate that MFG represent a unique source of MEC RNA to noninvasively sample sufficient amounts of high-quality RNA to assess the dynamics of MEC gene expression in vivo, especially during the first steps of infection, thereby paving the way for the discovery of early biomarkers for the control of intramammary infections. Furthermore, this noninvasive technique could be used to provide mammary transcriptomic data on a large scale, thus filling the gap between genomic and phenotypic data.

Taurine attenuates lipopolysaccharide-induced disfunction in mouse mammary epithelial cells

The intent of this study was to evaluate the active defense reaction of mouse mammary epithelial cells and the cytoprotective and anti-inflammatory properties of taurine to lipopolysaccharide (LPS)-induced disfunction in mouse mammary epithelial cells. (1) Primary cultured mouse mammary epithelial cells were stimulated with LPS for 24 h (final concentration=0, 5, 10, 20 μg/mL). Western blotting demonstrated a significant decrease in the secretion of β-casein in the 20 μg/mL LPS treatment group (P<0.05), while nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), lactoferrin (LF) and N-acetyl-β-D-glucosaminidase (NAGase) were all significantly increased following LPS treatment (P<0.01). Furthermore, cell survival was significantly inhibited after treatment with 20 μg/mL LPS; however, neither 5 μg/mL nor 10 μg/mL LPS had any effect on cell survival. Therefore, a level of 10 μg/mL LPS was selected to test the protective effect of taurine on mouse mammary epithelial cells. (2) Primary cultured mouse mammary epithelial cells were treated with 0, 5, 15 or 45 mmol/L taurine for 3 h, followed by 10 μg/mL LPS for 24 h. Taurine significantly attenuated the LPS-induced increase in NAGase activity, NO concentrations and the level of TNF-α, IL-1β, IL-6 and LF. Taurine at 45 mmol/L markedly increased β-casein secretion in response to LPS-induced disfunction. This study demonstrated that the addition of taurine to a culture medium significantly inhibited the LPS-induced release of inflammatory factors and increased β-casein secretion from mammary epithelial cells, thereby providing a possible explanation for the protective effect proposed for taurine in the prevention of LPS-induced disfunction in mammary epithelial cells.

Staphylococcal-associated molecular patterns enhance expression of immune defense genes induced by IL-17 in mammary epithelial cells

Interleukin-17A (IL-17A) and IL-17F have been shown to mediate a crucial crosstalk between the immune system and various epithelial tissues, stimulating various defensive mechanisms to bacterial infections. A number of studies have characterized the response to IL-17A and IL-17F of epithelial cells from airways, intestine, and skin, but not from the mammary gland. To evaluate the potential contribution of IL-17 to the immune defense of the mammary gland, we analyzed the effects of recombinant bovine IL-17A and IL-17F on primary bovine mammary epithelial cells (MEC) by quantitative PCR and ELISA. We found expression (mRNA) of the two components of the IL-17 receptor complex, IL-17RA and IL-17RC, in mammary tissue and MEC in vitro. The expression of a number of genes encoding cytokines, chemokines and proteins endowed with antibacterial activities was increased by IL-17A, and to a lesser extent by IL-17F, but the magnitude of responses was modest. As expected, responses were augmented by the combination of IL-17A or IL-17F with TNF-α. Interestingly, responses of a few of the tested genes, such as IL8, CCL20, iNOS, and CfB, were augmented by the combination of IL-17A with staphylococcal lipoteichoic acid or muramyl dipeptide, bacterial agonists of the innate immune system. This can be interpreted as indicating that IL-17A and IL-17F are tailored to exert their full potential in a septic environment. MEC responses were characterized by the expression of chemokines targeting not only neutrophils (CXCL3 and CXCL8) but also mononuclear leucocytes (CCL2, CCL20). Production of IL-6 was low and the inflammatory cytokines TNF-α and IL-1β were expressed (mRNA) but proteins were not secreted. Altogether, our results suggest that IL-17A and IL-17F have a potential to modulate the mammary gland immune response to mastitis-causing pathogens.

Acute-phase proteins: As diagnostic tool

The varied reactions of the host to infection, inflammation, or trauma are collectively known as the acute-phase response and encompass a wide range of pathophysiological responses such as pyrexia, leukocytosis, hormone alterations, and muscle protein depletion combining to minimize tissue damage while enhancing the repair process. The mechanism for stimulation of hepatic production of acute-phase proteins is by proinflammatory cytokines. The functions of positive acute-phase proteins (APP) are regarded as important in optimization and trapping of microorganism and their products, in activating the complement system, in binding cellular remnants like nuclear fractions, in neutralizing enzymes, scavenging free hemoglobin and radicals, and in modulating the host's immune response. APP can be used as diagnostic tool in many diseases like bovine respiratory syncytial virus, prostate cancer, bronchopneumonia, multiple myeloma, mastitis, Streptococcus suis infection, starvation, or lymphatic neoplasia. Thus, acute-phase proteins may provide an alternative means of monitoring animal health.

Natural variation in biomarkers indicating mastitis in healthy cows

Dairy herds are expanding and, with increasing numbers of animals in each herd, there is a need for automatic recording of indicators in milk in order to detect mastitis, inflammation of the udder. A number of biomarkers for mastitis have been suggested over the years. Mastitis usually occurs in one of the four udder quarters and since it is now possible to milk each udder quarter separately in automated milking systems, it is important to evaluate the normal variation in the biomarkers at udder quarter level. This study evaluated the normal variations between milkings for some biomarkers in clinically healthy cows, determined by repeated somatic cell count and bacteriological analysis. The biomarkers studied were serum amyloid A (SAA), haptoglobin (Hp), lactate dehydrogenase (LDH), N-acetyl-β-d-glucosaminidase (NAGase) and alkaline phosphatase (AP), parameters that have been suggested as markers for mastitis. Ten cows were monitored on 42 consecutive milking occasions through collection of udder quarter milk samples and representative cow composite milk samples, giving a total of 2100 individual milk samples. Each cow had its individual profile for the concentrations and variations in the parameters analysed. Although there was relatively large variation between cows for the biomarkers analysed, the variation between milkings in clinically healthy quarters within cows was often below 10%. The biomarker with the lowest variation in this study was LDH. The results suggest that comparing quarters within an individual cow can identify deviations from the natural variations between milkings. This could be a valuable tool instead of, or in combination with, a cut-off value for each parameter in order to detect changes in the milk indicating mastitis.

Transcriptional profiling of the acute pulmonary inflammatory response induced by LPS: role of neutrophils

Background

Lung cancer often develops in association with chronic pulmonary inflammatory diseases with an influx of neutrophils. More detailed information on inflammatory pathways and the role of neutrophils herein is a prerequisite for understanding the mechanism of inflammation associated cancer.

Methods

In the present study, we used microarrays in order to obtain a global view of the transcriptional responses of the lung to LPS in mice, which mimics an acute lung inflammation. To investigate the influence of neutrophils in this process, we depleted mice from circulating neutrophils by treatment with anti-PMN antibodies prior to LPS exposure.

Results

A total of 514 genes was greater than 1.5-fold differentially expressed in the LPS induced lung inflammation model. 394 of the 514 were up regulated genes mostly involved in cell cycle and immune/inflammation related processes, such as cytokine/chemokine activity and signalling. Down regulated genes represented nonimmune processes, such as development, metabolism and transport. Notably, the number of genes and pathways that were differentially expressed, was reduced when animals were depleted from circulating neutrophils, confirming the central role of neutrophils in the inflammatory response. Furthermore, there was a significant correlation between the differentially expressed gene list and the promutagenic DNA lesion M₁dG, suggesting that it is the extent of the immune response which drives genetic instability in the inflamed lung. Several genes that were specifically regulated by the presence of activated neutrophils could be identified and these were mostly involved in interferon signalling, oxidative stress response and cell cycle progression. The latter possibly refers to a higher rate of cell turnover in the inflamed lung with neutrophils, suggesting that the neutrophil influx is associated with a higher risk for the accumulation and fixation of mutations.

Conclusion

Gene expression profiling identified specific genes and pathways that are related to neutrophilic inflammation and could be associated to cancer development and indicate an active role of neutrophils in mediating the LPS induced inflammatory response in the mouse lung.

Haptoglobin and serum amyloid A in bulk tank milk in relation to raw milk quality

The aim of the present study was to evaluate relationships between the presence of the two major bovine acute phase proteins haptoglobin (Hp) and serum amyloid A (SAA) and raw milk quality parameters in bulk tank milk samples. Hp and SAA have been suggested as specific markers of mastitis but recently also as markers for raw milk quality. Since mastitis has detrimental effects on milk quality, it is important to investigate whether the presence of Hp or SAA indicates such changes in the composition and properties of the milk. Bulk tank milk samples (n=91) were analysed for Hp, SAA, total protein, casein, whey protein, proteolysis, fat, lactose, somatic cell count and coagulating properties. Samples with detectable levels of Hp had lower casein content, casein number and lactose content, but higher proteolysis than samples without Hp. Samples with detectable levels of SAA had lower casein number and lactose content, but higher whey protein content than samples without SAA. The presence of acute phase proteins in bulk tank milk is suggested as an indicator for unfavourable changes in the milk composition, e.g. protein quality, due to udder health disturbances, with economical implications for the dairy industry.

A sentinel function for teat tissues in dairy cows: dominant innate immune response elements define early response to E. coli mastitis

Escherichia coli intramammary infection elicits localized and systemic responses, some of which have been characterized in mammary secretory tissue. Our objective was to characterize gene expression patterns that become activated in different regions of the mammary gland during the acute phase of experimentally induced E. coli mastitis. Tissues evaluated were from Fürstenburg's rosette, teat cistern (TC), gland cistern (GC), and lobulo-alveolar (LA) regions of control and infected mammary glands, 12 and 24 h after bacterial (or control) infusions. The main networks activated by E. coli infection pertained to immune and inflammatory response, with marked induction of genes encoding proteins that function in chemotaxis and leukocyte activation and signaling. Genomic response at 12 h post-infection was greatest in tissues of the TC and GC. Only at 24 h post-infection did tissue from the LA region respond, at which time the response was the greatest of all regions. Similar genetic networks were impacted in all regions during early phases of intramammary infection, although regional differences throughout the gland were noted. Data support an important sentinel function for the teat, as these tissues responded rapidly and intensely, with production of cytokines and antimicrobial peptides.

The acute-phase protein serum amyloid A3 is expressed in the bovine mammary gland and plays a role in host defence

The serum amyloid A protein is one of the major reactants in the acute-phase response. Using representational difference analysis comparing RNA from normal and involuting quarters of a dairy cow mammary gland, we found an mRNA encoding the SAA3 protein (M-SAA3). The M-SAA3 mRNA was localized to restricted populations of bovine mammary epithelial cells (MECs). It was expressed at a moderate level in late pregnancy, at a low level through lactation, was induced early in milk stasis, and expressed at high levels in most MECs during mid to late involution and inflammation/mastitis. The mature M-SAA3 peptide was expressed in Escherichia coli, antibodies made, and shown to have antibacterial activity against E. coli, Streptococcus uberis and Pseudomonas aeruginosa. These results suggest that the mammary SAA3 may have a role in protection of the mammary gland during remodelling and infection and possibly in the neonate gastrointestinal tract.

Acute phase response in two consecutive experimentally induced E. coli intramammary infections in dairy cows

Background

Acute phase proteins haptoglobin (Hp), serum amyloid A (SAA) and lipopolysaccharide binding protein (LBP) have suggested to be suitable inflammatory markers for bovine mastitis. The aim of the study was to investigate acute phase markers along with clinical parameters in two consecutive intramammary challenges with Escherichia coli and to evaluate the possible carry-over effect when same animals are used in an experimental model.

Methods

Mastitis was induced with a dose of 1500 cfu of E. coli in one quarter of six cows and inoculation repeated in another quarter after an interval of 14 days. Concentrations of acute phase proteins haptoglobin (Hp), serum amyloid A (SAA) and lipopolysaccharide binding protein (LBP) were determined in serum and milk.

Results

In both challenges all cows became infected and developed clinical mastitis within 12 hours of inoculation. Clinical disease and acute phase response was generally milder in the second challenge. Concentrations of SAA in milk started to increase 12 hours after inoculation and peaked at 60 hours after the first challenge and at 44 hours after the second challenge. Concentrations of SAA in serum increased more slowly and peaked at the same times as in milk; concentrations in serum were about one third of those in milk. Hp started to increase in milk similarly and peaked at 36–44 hours. In serum, the concentration of Hp peaked at 60–68 hours and was twice as high as in milk. LBP concentrations in milk and serum started to increase after 12 hours and peaked at 36 hours, being higher in milk. The concentrations of acute phase proteins in serum and milk in the E. coli infection model were much higher than those recorded in experiments using Gram-positive pathogens, indicating the severe inflammation induced by E. coli.

Conclusion

Acute phase proteins would be useful parameters as mastitis indicators and to assess the severity of mastitis. If repeated experimental intramammary induction of the same animals with E. coli is used in cross-over studies, the interval between challenges should be longer than 2 weeks, due to the carry-over effect from the first infection.

Amyloid A in equine colostrum and early milk

The objective of this study was to investigate the protein, amyloid A3 (AA3), in equine colostrum and early milk. We hypothesized that AA3 was consistently present in equine colostrum and early milk, that no correlation existed between serum and colostrum concentrations of this protein in individual mares at parturition and that colostrum/milk concentrations of this mammary protein may be affected by age, breed, length of gestation and/or induction of parturition. Thirty-eight peripartum mares and seven non-pregnant, non-lactating mares were included in the study. Mean serum concentrations of this protein in the pregnant and non-pregnant mares were consistent with previous reports. Amyloid A3 was found in all colostrum and early milk samples at consistently higher concentrations than in peripartum maternal serum. There was no correlation between serum AA and colostrum AA3 concentrations at parturition. Age and breed effects were not significant. Increased gestation length and induction of parturition were associated with decreased colostrum and milk AA3 concentrations. We conclude that AA3 is consistently present in equine colostrum and early milk. The production of this protein in the mammary gland is likely to be under different stimulus to the production of serum AA, and may have protective effects in the neonatal intestine.

Ichthyophthirius multifiliis infection induces massive up-regulation of serum amyloid A in carp (Cyprinus carpio)

A real time quantitative PCR (RQ-PCR) assay was developed for measurement of differential expression of the genes encoding the acute phase reactant serum amyloid A (SAA), transferrin (TF) and a C-type lectin molecule (CL) in skin, blood and liver from Cyprinus carpio following infection with the ectoparasite Ichthyophthirius multifiliis. Serum amyloid A and CL were constitutively expressed in all organs evaluated while TF transcripts were only detected in the liver. A dramatic up-regulation (1600 times) in the expression levels of SAA was observed in skin 36 h after the parasite infection. A similar increase in the number of RNA molecules encoding for SAA was observed in the liver. The CL expression was significantly down regulated in all the organs and no significant change was observed in the expression levels of the TF in the liver. These results indicate that SAA plays a major role in the acute phase response in fish infected with I. multifiliis and emphasize the importance of the fish skin as an active organ in response to an ectoparasite infection.

Influence of induction of parturition on the neonatal acute phase response in foals

The objectives of the present study were to determine whether induction of parturition in mares at term with low doses of oxytocin (2.5 i.u. i.v. every 20 min) affected the incidence of peri-partum complications or inflammatory responses in the neonatal foal. Parturition was induced in 11 of 26 mares and the remainder foaled spontaneously. Serum concentrations of amyloid A (AA; an acute phase protein) were measured (with a commercial ELISA) from 0 to 72 h postpartum in 18 of the neonatal foals. The incidence of dystocia and premature placental separation was higher in induced mares (2 of 11 and 1 of 11 versus 0 of 15 and 0 of 15, respectively), whereas retained fetal membranes were more common in spontaneous foalings (2 of 15 versus 0 of 11). When abnormal foals were excluded (to decrease the influence of endogenous serum AA elevations), serum concentrations of AA increased to the same extent over time in foals with induced versus spontaneous parturition; foals with spontaneous parturition had a mean serum AA concentration of 7.8 microg/mL at birth that increased to a maximum of 58.9 microg/mL at 36 h; foals with induced parturition had a mean serum AA concentration of 5.4 microg/mL at birth that increased to a maximum of 41.4 microg/mL at 48 h. Baseline serum AA concentrations were lower in induced foals. We concluded that inducing parturition with low doses of oxytocin in mares at term did not affect (relative to spontaneous parturition) the temporal dynamics of serum AA concentrations in the normal foal in the first 72 h of life. However, the induction procedure may lead to complications during parturition that, if not detected early, could result in the development of an inflammatory response in the neonate.

Bovine serum amyloid A3 gene structure and promoter analysis: induced transcriptional expression by bacterial components and the hormone prolactin

Regulation of the bovine Saa3 promoter in response to signaling molecules associated with lactation or bacterial infection was assessed using a luciferase reporter system. Although the liver is the primary site for the production of acute phase proteins, typically serum amyloid A1 (SAA1) and serum amyloid A2 (SAA2), analysis of the differential expression of serum amyloid A3 (SAA3) by mammary epithelial cells is limited. Gram-negative bacterial lipopolysaccharide (LPS) and the Gram-positive bacterial lipoteichoic acid (LTA) substantially upregulated transcriptional expression driven by the Saa3 promoter in bovine mammary epithelial cells by 18.5-fold and 12.5-fold, respectively, whereas the lactogenic hormone, prolactin (PRL) stimulated a 3.5-fold increase. The minimal Saa3 promoter fragment that retained responsiveness to LPS, LTA, or PRL was 352 bp in size. A 1056 bp Saa3 promoter region exhibited the highest level of LPS or LTA inducible activity. This activity was 2-fold higher than the constitutive activity obtained with the Simian Virus 40 (SV40) promoter. The 53 bp 5' untranslated region (UTR) in exon 1 of the Saa3 gene enhanced expression levels in response to the stimulants LPS and LTA and the AT-rich region between nt -2571 and -2338 in the Saa3 promoter contained an enhancer that negated a silencer region(s) located between nt -2338 and -1003. Collectively, these data support the proposal that SAA3 serves an important tissue-specific function for the welfare of the mammary gland during both bacterial infection and tissue remodeling.

Gene expression profiling in lung tissues from mice exposed to cigarette smoke, lipopolysaccharide, or smoke plus lipopolysaccharide by inhalation

The purpose of this study was to investigate whether coexposure to lipopolysacchride (LPS) will heighten the inflammatory response and other pulmonary lesions in mice exposed to cigarette smoke, and thus to evaluate the potential use of this LPS-compromised mouse model as a model for chronic obstructive pulmonary disease (COPD) investigation. AKR/J male mice were exposed to HEPA-filtered air (sham control group), cigarette smoke (smoke group), LPS (LPS group), or smoke plus LPS (smoke-LPS group) by nose-only inhalation. Lungs were collected at the end of the 3-wk exposure and processed for microarray analysis. Clustering and network analysis showed decreased heat-shock response and chaperone activity, increased immune and inflammatory response, and increased mitosis in all three exposed groups. Two networks/function modules were exclusively found in the smoke-LPS group, that is, the downregulated muscle development/muscle contraction process and the upregulated reactive oxygen species production process. Notably, the number of genes and function modules/networks associated with inflammation was reduced in the smoke-LPS group compared to the LPS group. The most upregulated gene in the smoke group, MMP12, is a matrix metalloproteinase that preferentially degrades elastin and has been implicated in COPD development. NOXO1, which was upregulated in all three treatment groups, positively regulates the expression of a subunit of NADPH oxidase (NOX1), a major source of reactive oxygen species, and may play an important role in the pathogenesis of COPD. Serum amyloid A1, which is an acute-phase systemic inflammation marker and can be induced by LPS exposure, was significantly upregulated in the LPS and smoke-LPS groups. MARCO, a scavenger receptor expressed in macrophages that may play a significant role in LPS-induced inflammatory response, was upregulated in the LPS group and the smoke-LPS group, but not in the smoke group. In conclusion, gene expression profiling identified genes and function modules that may be related to COPD pathogenesis and may be useful as biomarkers to monitor COPD progression. In addition, an LPS-compromised mouse model showed potential as a useful tool for studying cigarette smoke-associated COPD.

Acute phase reaction and acute phase proteins

A review of the systemic acute phase reaction with major cytokines involved, and the hepatic metabolic changes, negative and positive acute phase proteins (APPs) with function and associated pathology is given. It appears that APPs represent appropriate analytes for assessment of animal health. Whereas they represent non-specific markers as biological effect reactants, they can be used for assessing nutritional deficits and reactive processes, especially when positive and negative acute phase variables are combined in an index. When such acute phase index is applied to separate healthy animals from animals with some disease, much better results are obtained than with single analytes and statistically acceptable results for culling individual animals may be reached. Unfortunately at present no cheap, comprehensive and easy to use system is available for assessing various acute phase proteins in serum or blood samples at the same time. Protein microarray or fluid phase microchip technology may satisfy this need; and permit simultaneous analysis of numerous analytes in the same small volume sample and enable integration of information derived from systemic reactivity and nutrition with disease specific variables. Applying such technology may help to solve health problems in various countries not only in animal husbandry but also in human populations.

Acute phase reactants, challenge in the near future of animal production and veterinary medicine

The future of acute phase proteins (APPs) in science is discussed in this paper. Many functions and associated pathological processes of APPs are unknown. Extrahepatic formation in local tissues needs attention. Local serum amyloid A (SAA) formation may be involved in deposition of AA-amyloid induced by conformational change of SAA resulting in amyloid formation, having tremendous food safety implications. Amyloidogenesis is enhanced in mouse fed beta pleated sheet-rich proteins. The local amyloid in joints of chicken and mammary corpora amylacea is discussed. Differences in glycosylation of glycoproteins among the APPs, as has been shown for alpha1-acid glycoprotein, have to be considered. More knowledge on the reactivity patterns may lead to implication of APPs in the diagnostics and staging of a disease. Calculation of an index from values of several acute phase variables increases the power of APPs in monitoring unhealthy individuals in animal populations. Vaccinations, just as infections in eliciting acute phase response seem to limit the profitability of vaccines because acute phase reactions are contra-productive in view of muscle anabolism. Interest is focused on amino acid patterns and vitamins in view of dietary nutrition effect on sick and convalescing animals. When inexpensive methodology such as liquid phase methods (nephelometry, turbidimetry) or protein array technology for rapid APP measurement is available, APPs have a future in routine diagnostics. Specific groups of patients may be screened or populations monitored by using APP.

Staphylococcus aureus lipotechoic acid induces differential expression of bovine serum amyloid A3 (SAA3) by mammary epithelial cells: Implications for early diagnosis of mastitis

Mastitis is one of the most costly diseases of agriculturally important animals and is a common problem for lactating cows. Current methods used to detect clinical and especially subclinical mastitis are either inadequate or problematic. Pathogens such as the gram-positive bacterium Staphylococcus aureus or the gram-negative bacterium Escherichia coli typically cause mastitis. E. coli induces clinical mastitis, whereas, S. aureus causes a subclinical, chronic infection of the mammary gland. In this study we report the differential expression and secretion of mammary-derived serum amyloid A3 (SAA3) by bovine mammary epithelial cells following stimulation with the S. aureus cell wall component, lipotechoic acid (LTA). Two-dimensional immunoblot analyses confirmed that bovine SAA3 is the predominant SAA isoform produced by LTA stimulated mammary epithelial cells. Our previous study showed that bovine SAA3 is also differentially expressed in response to the gram-negative bacterial endotoxin lipopolysaccharide. Collectively, these data indicate that the local production of SAA3 by mammary epithelial cells in response to either gram-positive or gram-negative bacterial components may provide a sensitive indicator for early detection and treatment of mastitis in vivo, minimizing chronic cases of infection, the spread of mastitis to other animals, and economic losses.