Proteomic Evaluation of Inflammatory Proteins in Rat Spleen Interstitial Fluid and Lymph during LPS-Induced Systemic Inflammation Reveals Increased Levels of ADAMST1

Role of the afferent lymph as an immunological conduit to analyze tissue antigenic and inflammatory load

The lymphatic fluid is the conduit by which part of the tissue "omics" is transported to the draining lymph node for immunosurveillance. Following cannulation of the pre-nodal cervical and mesenteric afferent lymphatics, herein we investigate the lymph proteomic composition, uncovering that its composition varies according to the tissue of origin. Tissue specificity is also reflected in the dendritic cell-major histocompatibility complex class II-eluted immunopeptidome harvested from the cervical and mesenteric nodes. Following inflammatory disruption of the gut barrier, the lymph antigenic and inflammatory loads are analyzed in both mice and subjects with inflammatory bowel diseases. Gastrointestinal tissue damage reflects the lymph inflammatory and damage-associated molecular pattern signatures, microbiome-derived by-products, and immunomodulatory molecules, including metabolites of the gut-brain axis, mapped in the afferent mesenteric lymph. Our data point to the relevance of the lymphatic fluid to probe the tissue-specific antigenic and inflammatory load transported to the draining lymph node for immunosurveillance.

Treatment with bestatin (the exogenous synthetic inhibitor of metalloproteinases) reduces the activity of metalloproteinase 2 and 12 in the spleen and lung tissues of rats in a model of lipopolysaccharide-induced sepsis

Sepsis is caused by an inadequate or dysregulated host response to infection. Enzymes causing cellular degradation are matrix metalloproteinases (MMPs). Lipopolysaccharide (LPS) is used in models of sepsis in laboratory settings The aim of the study was to measure MMP 2 and 12 concentrations in spleen and lungs in rats in which septic shock was induced by LPS. The experiment was carried out on 40 male Wistar rats (5 groups of 8): 0. controls 1. administered LPS 2. administered bestatin 3. LPS and bestatin 4.bestatin and after 6 hours LPS Animals were decapitated. Lungs and spleens were collected. Concentrations of MMP-2 and MMP-12 were determined using immunoenzymatic methods. Mean (±SD) MMP-2 in the controls was 43.57 ± 20.53 ng/ml in the lungs and 1.7 ± 0.72 ng/ml in the spleen; Group 1: 31.28 ± 13.13 ng/ml, 0.83 ± 0.8 ng/ml; Group 2: 44.24 ± 22.75 ng /ml, 1.01 ± 0.32 ng/ml; Group 3: 35.94 ± 15.13 ng/ml, 0.41 ± 0.03 ng/ml; Group 4:79.42 ± 44.70 ng/ml, 0.45 ± 0.15, respectively. Mean MMP-12 in controls was 19.79 ± 10.01 ng/ml in lungs and 41.13 ± 15.99 ng/ml in the spleen; Group 1:27.97 ± 15.1 ng/ml; 40.44 ± 11.2 ng/ml; Group 2: 37.93 ± 25.38 ng/ml 41.05 ± 18.08 ng/ml; Group 3: 40.59 ± 11.46 ng/ml, 35.16 ± 12.89 ng/ml; Group 4: 39.4 ± 17.83 ng/ml, 42.04 ± 12.35 ng/ml, respectively. CONCLUSIONS: 1. Bestatin reduces MMP 2 and 12 levels in spleen and lungs. 2. Treatment with bestatin minimizes the effect of LPS.

Genome-wide identification of bovine ADAMTS gene family and analysis of its expression profile in the inflammatory process of mammary epithelial cells

ADAM metallopeptidase with thrombospondin type 1 motif (ADAMTS) are secreted, multi-domain matrix-related zinc endopeptidases that play a role in organogenesis, assembly and degradation of extracellular matrix (ECM), cancer and inflammation. Genome-wide identification and analysis of the bovine ADAMTS gene family has not yet been carried out. In this study, 19 ADAMTS family genes were identified in Bos taurus by genome-wide bioinformatics analysis, and they were unevenly distributed on 12 chromosomes. Phylogenetic analysis shows that the Bos taurus ADAMTS are divided into eight subfamilies, with highly consistent gene structures and motifs within the same subfamily. Collinearity analysis showed that the Bos taurus ADAMTS gene family is homologous to other bovine subfamily species, and many ADAMTS genes may be derived from tandem replication and segmental replication. In addition, based on the analysis of RNA-seq data, we found the expression pattern of ADAMTS gene in different tissues. Meanwhile, we also analyzed the expression profile of ADAMTS gene in the inflammatory response of bovine mammary epithelial cells (BMECs) stimulated by LPS by qRT-PCR. The results can provide ideas for understanding the evolutionary relationship and expression pattern of ADAMTS gene in Bovidae, and clarify the theoretical basis of the function of ADAMTS in inflammation.

Isolation of lymph shows dysregulation of STAT3 and CREB pathways in the spleen and liver during leukemia development in a rat model

BACKGROUND AND AIMS

Acute myeloid leukemia (AML) is a heterogeneous malignant condition characterized by massive infiltration of poorly differentiated white blood cells in the blood stream, bone marrow, and extramedullary sites. During leukemic development, hepatosplenomegaly is expected to occur because large blood volumes are continuously filtered through these organs. We asked whether infiltration of leukemic blasts initiated a response that could be detected in the interstitial fluid phase of the spleen and liver.

MATERIAL AND METHODS

We used a rat model known to mimic human AML in growth characteristics and behavior. By cannulating efferent lymphatic vessels from the spleen and liver, we were able to monitor the response of the microenvironment during AML development.

RESULTS AND DISCUSSION

Flow cytometric analysis of lymphocytes showed increased STAT3 and CREB signaling in spleen and depressed signaling in liver, and proteins related to these pathways were identified with a different profile in lymph and plasma in AML compared with control. Additionally, several proteins were differently regulated in the microenvironment of spleen and liver in AML when compared with control.

CONCLUSION

Interstitial fluid, and its surrogate efferent lymph, can be used to provide unique information about responses in AML-infiltered organs and substances released to the general circulation during leukemia development.

Keratinocytes coordinate inflammatory responses and regulate development of secondary lymphedema

Epidermal changes are histological hallmarks of secondary lymphedema, but it is unknown if keratinocytes contribute to its pathophysiology. Using clinical lymphedema specimens and mouse models, we show that keratinocytes play a primary role in lymphedema development by producing T-helper 2 (Th2) -inducing cytokines. Specifically, we find that keratinocyte proliferation and expression of protease-activated receptor 2 (PAR2) are early responses following lymphatic injury and regulate the expression of Th2-inducing cytokines, migration of Langerhans cells, and skin infiltration of Th2-differentiated T cells. Furthermore, inhibition of PAR2 activation with a small molecule inhibitor or the proliferation inhibitor teriflunomide (TF) prevents activation of keratinocytes stimulated with lymphedema fluid. Finally, topical TF is highly effective for decreasing swelling, fibrosis, and inflammation in a preclinical mouse model. Our findings suggest that lymphedema is a chronic inflammatory skin disease, and topically targeting keratinocyte activation may be a clinically effective therapy for this condition.

Detectable A Disintegrin and Metalloproteinase With Thrombospondin Motifs-1 in Serum Is Associated With Adverse Outcome in Pediatric Sepsis

Supplemental Digital Content is available in the text.

A Disintegrin and Metalloproteinase with Thrombospondin Motifs-1 is hypothesized to play a role in the pathogenesis of invasive infection, but studies in sepsis are lacking.

A coumarin-based TICT fluorescent probe for real-time fluorescence lifetime imaging of mitochondrial viscosity and systemic inflammation in vivo

Systemic inflammation, linked with abnormal mitochondrial viscosity, is reported to be associated with cerebro-cardiovascular disease and Alzheimer's disease. Therefore, it is of great significance to detect the mitochondrial viscosity to indicate the inflammatory signal in vivo. Considering the strategies of fluorescent molecular rotors (FMRs) and fluorescence lifetime imaging microscopy (FLIM), we have rationally designed a novel mitochondrial viscosity-specific fluorescent probe Mito-VCI, based on coumarin fluorophores with benzo[e]indolium as the rotor group. In a high viscosity solution system, the fluorescence lifetime of the probe Mito-VCI was prolonged due to the planarization and rigidity enhancement of the molecular rotor. Satisfactorily, the probe was only sensitive to viscosity, instead of non-viscosity factors such as pH and polarity. Furthermore, the probe sensitively targeted mitochondria in HeLa cells with a Pearson's correlation of 0.93, and specifically detected dynamics variation of mitochondrial viscosity with FLIM imaging in HeLa cells induced by LPS. Notably, significant fluorescence lifetime changes of Mito-VCI between normal and inflammatory tissues also occurred (for example, the fluorescence lifetime in the spleen changed from 1.128 to 1.432 ns). It can be inferred from the above observations that Mito-VCI could work as an effective and sensitive fluorescent molecular rotor for mitochondrial viscosity monitoring through FLIM imaging with a systemic inflammatory response, and provide potential applications for the diagnosis of systemic inflammation in pharmacology and toxicology studies.

Hypericum perforatum L. Regulates Glutathione Redox Stress and Normalizes Ggt1/Anpep Signaling to Alleviate OVX-Induced Kidney Dysfunction

Menopause and associated renal complications are linked to systemic redox stress, and the causal factors remain unclear. As the role of Hypericum perforatum L. (HPL) in menopause-induced kidney disease therapy is still ambiguous, we aim to explore the effects of HPL on systemic redox stress under ovariectomy (OVX)-induced kidney dysfunction conditions. Here, using combined proteomic and metabolomic approaches, we constructed a multi-scaled “HPL-disease-gene-metabolite” network to generate a therapeutic “big picture” that indicated an important link between glutathione redox stress and kidney impairment. HPL exhibited the potential to maintain cellular redox homeostasis by inhibiting gamma-glutamyltransferase 1 (Ggt1) overexpression, along with promoting the efflux of accumulated toxic amino acids and their metabolites. Moreover, HPL restored alanyl-aminopeptidase (Anpep) expression and metabolite shifts, promoting antioxidative metabolite processing, and recovery. These findings provide a comprehensive description of OVX-induced glutathione redox stress at multiple levels and support HPL therapy as an effective modulator in renal tissues to locally influence the glutathione metabolism pathway and subsequent redox homeostasis.

Cuprizone and EAE mouse frontal cortex proteomics revealed proteins altered in multiple sclerosis

Two pathophysiological different experimental models for multiple sclerosis were analyzed in parallel using quantitative proteomics in attempts to discover protein alterations applicable as diagnostic-, prognostic-, or treatment targets in human disease. The cuprizone model reflects de- and remyelination in multiple sclerosis, and the experimental autoimmune encephalomyelitis (EAE, MOG1-125) immune-mediated events. The frontal cortex, peripheral to severely inflicted areas in the CNS, was dissected and analyzed. The frontal cortex had previously not been characterized by proteomics at different disease stages, and novel protein alterations involved in protecting healthy tissue and assisting repair of inflicted areas might be discovered. Using TMT-labelling and mass spectrometry, 1871 of the proteins quantified overlapped between the two experimental models, and the fold change compared to controls was verified using label-free proteomics. Few similarities in frontal cortex between the two disease models were observed when regulated proteins and signaling pathways were compared. Legumain and C1Q complement proteins were among the most upregulated proteins in cuprizone and hemopexin in the EAE model. Immunohistochemistry showed that legumain expression in post-mortem multiple sclerosis brain tissue (n = 19) was significantly higher in the center and at the edge of white matter active and chronic active lesions. Legumain was associated with increased lesion activity and might be valuable as a drug target using specific inhibitors as already suggested for Parkinson's and Alzheimer's disease. Cerebrospinal fluid levels of legumain, C1q and hemopexin were not significantly different between multiple sclerosis patients, other neurological diseases, or healthy controls.

The protective effects of the Ganoderma atrum polysaccharide against acrylamide-induced inflammation and oxidative damage in rats

In this study, the protective effects of the Ganoderma atrum polysaccharide (PSG-1) on selected tissue (liver, spleen, kidneys and intestine) toxicity induced by acrylamide (AA) in SD rats were investigated. The results showed that pretreatment with PSG-1 could prevent AA-induced damage to liver and kidney functions by increasing the activities of ALT, AST and ALP and the levels of TG, BUN and CR in the serum of AA-treated rats. PSG-1 could also maintain the intestinal barrier function and permeability by preventing the reduction of the serum d-Lac and ET-1 levels in the intestine of AA-treated rats. In addition, AA-induced DNA damage, as indicated by an increase of the 8-OHdG level, was alleviated by pretreatment with PSG-1. Histological observations of the tissues confirmed the protective effects of different doses of PSG-1. Moreover, PSG-1 supplementation reduced oxidative stress and inflammation in rats by upregulating the superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities and IL-10 levels, and preventing the overproduction of malondialdehyde (MDA), IL-1β, IL-6, and TNF-α. Thus, these findings suggest that PSG-1 effectively prevents AA-induced damage in the liver, spleen, kidneys, and intestine of rats, partially by alleviating the inflammatory response and oxidative stress and protecting the intestinal integrity and barrier function.

ADAMTS proteases and the tumor immune microenvironment: Lessons from substrates and pathologies

The relationship of ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) proteases with inflammatory processes was anticipated since their discovery. Although knowledge of these extracellular proteases in different contexts continues to grow, many questions remain unanswered. In this review, we summarize the most important studies of ADAMTSs and their substrates in inflammation and in the immune system of non-oncological disorders. In addition, we update the findings on cancer and highlight their emerging role in the tumor immune microenvironment. Although the overall functions of extracellular molecules are known to be modulated by proteolysis, specific activities attributed to intact proteins and cleaved fragments in the context of inflammation are still subject to debate. A better understanding of ADAMTS activities will help to elucidate their contribution to the immune phenotype and to open up new therapeutic and diagnostic possibilities.

MiR-181d-5p Targets KLF6 to Improve Ischemia/Reperfusion-Induced AKI Through Effects on Renal Function, Apoptosis, and Inflammation

Renal tubular epithelial cell (RTEC) death and renal interstitial inflammation are the most crucial pathophysiological changes in acute kidney ischemia/reperfusion injury (IRI). The microRNA (miR)-181d family plays diverse roles in cell proliferation, apoptosis and inflammation, but its renal target and potential role in IRI are unknown. Here, we showed that the expression of miR-181d-5p decreased and Krueppel-like factor 6 (KLF6) increased in a renal cell (HK-2) model of hypoxia/reoxygenation (H/R) injury and a mouse model of renal IRI. They were mainly distributed in the renal tubules. After renal IRI, miR-181d-5p overexpression significantly inhibited inflammatory mediators, reduced apoptosis and further improved renal function. KLF6 exacerbated RTEC damage and acted as a NF-κB co-activator to aggravate the renal IRI inflammatory response. Mechanistically, KLF6 was predicted as a new potential target gene of miR-181d-5p through bioinformatic analysis and luciferase reporter assay verification. After overexpressing miR-181d-5p and inhibiting KLF6, the role of miR-181d-5p was weakened on the renal damage improvement. In conclusion, miR-181d-5p upregulation produced protective antiapoptotic and anti-inflammatory effects against IRI in kidneys in vivo and H/R injury in HK-2 cells in vitro, and these effects were achieved by targeted inhibition of KLF6. Thus, our results provide novel insights into the molecular mechanisms associated with IRI and a potential novel therapeutic target.

A disintegrin-like and metalloproteinase with thrombospondin-1 (ADAMTS-1) levels in gingival crevicular fluid correlate with vascular endothelial growth factor-A, hypoxia-inducible factor-1α, and clinical parameters in patients with advanced periodontitis

BACKGROUND

ADAMTS (a disintegrin-like and metalloproteinase with thrombospondin) are a family of proteinases that are structurally similar to the family of matrix metalloproteinases with critical roles in damage and repair of the extracellular matrix. Their functions are closely related to inflammation, hypoxia, and vascularization. Our aim was to determine levels of ADAMTS-1 in gingival crevicular fluid (GCF) in patients with advanced periodontal diseases and identify their association with hypoxia-inducible factor-1alpha (HIF-1α), vascular endothelial growth factor (VEGF-A), and clinical parameters of periodontitis.

METHODS

The study consisted of three groups: healthy individuals (control; n = 20), generalized chronic periodontitis (CP; n = 21), and generalized aggressive periodontitis (GAgP; n = 20). Clinical parameters were measured. Levels of ADAMTS-1, VEGF-A, and HIF-1α in GCF and serum were quantified by enzyme-linked immunosorbent assay (ELISA) and reported as total amounts and concentration.

RESULTS

ADAMTS-1 total amount in GCF were significantly higher in patients with CP and GAgP compared with healthy individuals (P < 0.05). HIF-1α total amount in GCF were also higher in periodontitis groups compared with the control group (P < 0.05). GCF total VEGF-A content was significantly higher in the GAgP group compared with the CP and the controls (respectively; P = 0.023, P = 0.003). There was a significant correlation between ADAMTS-1, VEGF-A, and HIF-1α levels in the GCF and clinical periodontal parameters (probing depth [PD], bleeding on probing [BOP], and clinical attachment loss (CAL); P < 0.05).

CONCLUSION

ADAMTS-1 may play a role in advanced periodontal disease pathogenesis in correlation with tissue hypoxia and vascularization.

Lymphatic Vessel Network Structure and Physiology

The lymphatic system is comprised of a network of vessels interrelated with lymphoid tissue, which has the holistic function to maintain the local physiologic environment for every cell in all tissues of the body. The lymphatic system maintains extracellular fluid homeostasis favorable for optimal tissue function, removing substances that arise due to metabolism or cell death, and optimizing immunity against bacteria, viruses, parasites, and other antigens. This article provides a comprehensive review of important findings over the past century along with recent advances in the understanding of the anatomy and physiology of lymphatic vessels, including tissue/organ specificity, development, mechanisms of lymph formation and transport, lymphangiogenesis, and the roles of lymphatics in disease. © 2019 American Physiological Society. Compr Physiol 9:207-299, 2019.

ADAMTS1 protease is required for a balanced immune cell repertoire and tumour inflammatory response

Recent advances have emphasized the relevance of studying the extracellular microenvironment given its main contribution to tissue homeostasis and disease. Within this complex scenario, we have studied the extracellular protease ADAMTS1 (a disintegrin and metalloprotease with thrombospondin motif 1), implicated in vascularization and development, with reported anti- and pro-tumorigenic activities. In this work we performed a detailed study of the vasculature and substrates in adult organs of wild type and Adamts1-deficient mice. In addition to the expected alterations of organs like kidney, heart and aorta, we found that the lack of ADAMTS1 differently affects lymphocyte and myeloid populations in the spleen and bone marrow. The study of the substrate versican also revealed its alteration in the absence of the protease. With such premises, we challenged our mice with subcutaneous B16F1 syngeneic tumours and closely evaluated the immune repertoire in the tumours but also in the distant spleen and bone marrow. Our results confirmed a pro-inflammatory landscape in the absence of ADAMTS1, correlating with tumour blockade, supporting its novel role as a modulator of the immune cell response.

Sepsis Through the Eyes of Proteomics: The Progress in the Last Decade

Sepsis is a systemic inflammatory response caused by infection whose molecular mechanisms are still not completely understood. The early detection of sepsis remains a great challenge for clinicians because no single biomarker capable of its reliable prediction, hence, delayed diagnosis frequently undermines treatment efforts, thereby contributing to high mortality. There are several experimental approaches used to reveal the molecular mechanism of sepsis progression. Proteomics coupled with mass spectrometry made possible to identify differentially expressed proteins in clinical samples. Recent advancement in liquid chromatography-based separation methods and mass spectrometers resolution and sensitivity with absolute quantitation methods, made possible to use proteomics as a powerful tool for study of clinical samples with higher coverage proteome profiles. In recent years, number of proteomic studies have been done under sepsis and/or in response to endotoxin and showed various signaling pathways, functions, and biomarkers. This review enlightened the proteomic progress in the last decade in sepsis.

The Lymphatic Fluid

This review will highlight our current understanding of the formation, circulation, and immunological role of lymphatic fluid. The formation of the extracellular fluid depends on the net balance between the hydrostatic and osmotic pressure gradients effective in the capillary beds. Lymph originates from the extracellular fluid and its composition combines the ultrafiltrated plasma proteins with the proteome generated by the metabolic activities of each parenchymal tissue. Several analyses have indicated how the lymph composition reflects the organs' physiological and pathological states. The collected lymphatic fluid moves from the capillaries into progressively larger collectors toward the draining lymph node aided by the lymphangion contractility and unidirectional valves, which prevent backflow. The proteomic composition of the lymphatic fluid is reflected in the MHC II peptidome presented by nodal antigen-presenting cells. Taken together, the past few years have generated new interest in the formation, transport, and immunological role of the lymphatic fluid.

1,25-Dihydroxyvitamin-D3 induces brain proteomic changes in cuprizone mice during remyelination involving calcium proteins

Dietary supplementation of vitamin D is commonly recommended to patients with multiple sclerosis. We recently found that high-dose of the hormonally active 1,25-dihydroxyvitamin-D₃ (1,25D) promotes myelin repair in the cuprizone model for de- and remyelination. In the present study, we quantified 5062 proteins, of which 125 were differentially regulated in brain tissue from 1,25D treated mice during remyelination, compared to placebo. Proteins upregulated in the early remyelination phase were involved in calcium binding, e.g. calretinin (>1.3 fold, p < 0.005), S10A5 and secretagogin, and involved in mitochondrial function, e.g. NADH-ubiquinone oxidoreductase chain 3, and acyl-coenzyme A synthetase. Calretinin, S10A5 and secretagogin expression levels were characterized using immunohistochemistry. Calretinin immunoreactivity was significantly increased (>3 fold, p = 0.016) in the medial septal nuclei of 1,25D treated mice in the early remyelination phase. Our results indicate that vitamin D may influence remyelination by mechanisms involving an increase in calretinin expression and potentially other calcium binding proteins.

Temporal gene expression in the hippocampus and peripheral organs to endotoxin-induced systemic inflammatory response in caspase-1-deficient mice

OBJECTIVES

Caspase-1 (casp1), a key protease involved in the systemic inflammatory response syndrome (SIRS), controls the brain expression of a set of eight genes: Nos2 and Ptgs2 (nitric oxide synthase 2 and prostaglandin-endoperoxide synthase 2, two inducible enzymes), Cxcl1 and Cxcl10 (C-X-C motif chemokine ligand 1 and ligand 10), Tgtp and Gbp2 (T cell-specific GTPase 1 and guanylate-binding protein 2, two GTPases), Adamts1 (a disintegrin-like and metallopeptidase with thrombospondin type 1 motif, 1, a metalloprotease) and Il1rn (interleukin-1 receptor antagonist). Our objective was to ascertain whether casp1 also controlled the peripheral expression of these genes and, if so, to compare their central versus peripheral patterns of gene expression in immune and endocrine tissues during SIRS.

METHODS

Wild-type (wt) and casp1 knockout (casp1(-/-)) mice were injected with either saline or a high dose of endotoxin/lipopolysaccharide (LPS; 800 μg/mice i.p.). Saline-injected mice were immediately euthanized after injection, whereas LPS-injected mice were sacrificed 6 and 12 h after LPS administration. Hippocampal, splenic and adrenal gene expressions were determined by real-time PCR.

RESULTS

Overall, casp1(-/-) mice showed a lower inflammatory response than wt mice. The expression levels of powerful proinflammatory factors such as Nos2 and Ptgs2 was reduced in casp1(-/-) mice. Moreover, a hierarchical clustering analysis aimed at studying patterns of gene coexpression revealed large alterations in the hippocampal pattern of casp1(-/-) mice. Surprisingly, the expression of Adamts1 was increased in the hippocampus and adrenals of casp1(-/-) mice.

CONCLUSIONS

The resilience of casp1(-/-) mice to SIRS lethality is associated with a lower inflammatory response, loss of hippocampal gene coexpression patterns, and increased hippocampal Adamts1 gene expression. The latter might be beneficial for casp1(-/-) mice, since ADAMTS1 is likely to play a role in neuronal plasticity. The mechanisms described here may help the development of either novel biomarkers or therapeutic targets against SIRS/sepsis.

Age-related changes in rat dermal extracellular matrix composition affect the distribution of plasma proteins as a function of size and charge

Collagen and glycosaminoglycans (GAGs) constituting the ECM may limit the space available and thus exclude macromolecules from a fraction of the interstitial fluid (IF) phase. This exclusion phenomenon is of importance for transcapillary fluid and solute exchange. The purpose of the study was to examine the range of interstitial exclusion in rat skin by using probes within a span of molecular weights and electrical charge and also to test if a change in interstitial composition, occurring as a consequence of aging, affected exclusion. To this end, we used a novel approach, involving the exact determination of albumin concentration and mass in IF and tissue eluate by HPLC and thereafter, expressing the corresponding numbers relative to albumin for a set of probe proteins assessed by quantitative proteomics. Albumin was excluded from 55±4% (n=8) of the extracellular fluid phase. There was a highly significant, positive correlation between probe Stokes-Einstein (SE) radius and fractional excluded volume (VEF), described by VEF=0.078·SE radius+0.269 (P<0.001), and oppositely, a negative correlation between probe isoelectric point (pI) and exclusion for proteins with comparable size, VEF=-0.036·pI+0.719 (P=0.04). Aging resulted in a significant reduction in skin hydration and sulfated GAGs, a moderate increase in hyaluronan, and a corresponding, reduced VEF for albumin and the other macromolecular probes. Our findings suggest that the changes in the ECM in aged skin may result in delayed adjustments of fluid perturbations and reduced ability for salt storage.

The role of proteomics in understanding biological mechanisms of sepsis

Sepsis is a systemic inflammatory state caused by infection. Complications of this infection with multiple organ failure lead to more lethal conditions, such as severe sepsis and septic shock. Sepsis is one of the leading causes of US deaths. Novel biomarkers with high sensitivity and specificity may be helpful for early diagnosis of sepsis and for improvement of patient outcomes through the development of new therapies. Mass spectrometry-based proteomics offers powerful tools to identify such biomarkers and furthermore to give insight to fundamental mechanisms of this clinical condition. In this review, we summarize findings from proteomics studies of sepsis and how their applications have provided more understanding into the pathogenesis of septic infection. Literatures related to "proteomics", "sepsis", "systemic inflammatory response syndrome", "severe sepsis", "septic infection", and "multiple organ dysfunction syndrome" were searched using PubMed. Findings about neonatal and adult sepsis are discussed separately. Within the adult sepsis studies, results are grouped based on the models (e.g., human or animal). Across investigations in clinical populations and in rodent and mammalian animal models, biological pathways, such as inflammatory and acute phase response, coagulation, complement, mitochondrial energy metabolism, chaperones, and oxidative stress, are altered at the protein level. These proteomics studies have discovered many novel biomarker candidates of septic infection. Validation the clinical use of these biomarker candidates may significantly impact the diagnosis and prognosis of sepsis. In addition, the molecular mechanisms revealed by these studies may also guide the development of more effective treatments.

Prion protein participates in the protection of mice from lipopolysaccharide infection by regulating the inflammatory process

Despite the overwhelming evidence of the involvement of prion protein (PrP) in prion disease pathogenesis, the normal functions of this cell surface glycoprotein remain unclear. Previously, we showed that PrP may have a dual regulatory role by regulating the opposite poles of pro-inflammation and anti-inflammation as well as tissue repair in activated microglia. In the present work, we compared the mRNA expression of inflammation-related cytokines (TNF-α, IL-1β, IL-6, NOS2, and IL-10) and IL-4-related alternative activation markers (Arg1 and Mrc1) after lipopolysaccharide (LPS) challenge in the brain and spleen and examined peripheral leukocyte recovery and LPS-induced mortality in PrP knockout mice (PrP(-/-)) and wild-type (WT) mice. During the acute phase, WT mice exhibited higher levels of pro-inflammatory cytokines in the brain and spleen than in PrP(-/-) mice, while PrP(-/-) mice sustained higher levels of pro-inflammatory cytokines and lower levels of anti-inflammatory cytokines, Arg1, and Mrc1 during the later phase. PrP(-/-) mice also exhibited a slower peripheral leukocyte recovery process and higher mortality in response to LPS-induced septic shock. These results suggest that the PrP may participate in the protection of mice from LPS infection by regulating the process of inflammatory response.

ADAMTS1 inhibits lymphangiogenesis by attenuating phosphorylation of the lymphatic endothelial cell-specific VEGF receptor

Angiogenesis and lymphangiogenesis play roles in malignant tumor progression, dissemination, and metastasis. ADAMTS1, a member of the matrix metalloproteinase family, is known to inhibit angiogenesis. Recombinant ADAMTS1 was shown to strongly inhibit angiogenesis. We investigated whether ADAMTS1 inhibited lymphangiogenesis in the present study. We examined cell proliferation and cell migration in normal human dermal lymphatic microvascular endothelial cells (HMVEC-dLy) transduced with or without adenoviral human ADAMTS1 gene therapy. We then examined the VEGFC/VEGFR3 signal transduction pathway in ADAMTS1-transduced HMVEC-dLy. Cell proliferation and tube formation in Matrigel were significantly lower with transduced ADAMTS1 than with control (non-transduced HMVEC-dLy). The phosphorylation of VEGFR3 was also attenuated by ADAMTS1 gene therapy in HMVEC-dLy. Immunoprecipitation assays revealed that ADAMTS1 formed a complex with VEGFC. Our results demonstrated that ADAMTS1 inhibited lymphangiogenesis in vitro. The data highlight the new function of ADAMTS1 in the regulation of lymphangiogenesis and the therapeutic potential of ADAMTS1 in cancer therapy.

Identification and characterization of cow's milk proteins from the rat intestinal lymph using a proteomic strategy

Food proteins were considered to be absorbed into the body after being digested to amino acids, dipeptides, and tripeptides. However, there are studies indicating that some proteins can pass through the intestinal epithelium under normal physiological conditions, perhaps not in sufficient quantities to be of nutritional importance, but in quantities that may be antigenically or biologically active. In the present study, rat intestinal lymph samples were collected using a modified lymph fistula rat model in fasting and cow's milk postprandial states. Low molecular weight proteins were enriched by ultrafiltration and differential solubilization, separated by 1D-SDS-PAGE, digested in-gel based on molecular weight, and identified using nano-LC-MS/MS. In the postprandial rat intestinal lymph, nine bovine-specific proteins (false discovery rate ≤1%) were identified in different molecular weight regions. Most proteins identified in lymph were highly abundant proteins in the milk, such as β-lactoglobulin and caseins. Seven of the nine identified bovine-specific proteins are allergens in milk. This strategy can be used to search for proteins that can enter the intestinal lymph and analyze their common features. Understanding the common features of these proteins might help to develop protein drugs taken orally, so that therapeutic proteins might embody fusion domains for cross-barrier transport or translocation.