Transthyretin is an inhibitor of monocyte and endothelial cell interleukin-1 production

Assessment of the Safety and Efficacy of an Oral Probiotic-Based Vaccine Against Aspergillus Infection in Captive-Bred Humboldt Penguins (Spheniscus humboldti)

Aspergillosis is a fungal infection caused mainly by Aspergillus fumigatus that often results in respiratory disease in birds. Aspergillosis is a major cause of morbidity and mortality in captive-bred penguin species. Currently, there is no registered vaccine to prevent aspergillosis. Recent research demonstrated that oral administration of gram-negative bacteria expressing high levels of galactose-α-1,3-galactose (α-Gal) modulates anti-α-Gal immunity and protects turkeys from clinical aspergillosis caused by experimental A. fumigatus infection. The role of anti-α-Gal immunity in penguins has not been studied. Here, we tested the distribution of α-1,3-galactosyltransferase (α1,3GT) genes in the fecal microbiome of Humboldt penguins (Spheniscus humboldti). The occurrence of natural anti-α-Gal antibodies (Abs) in sera and eggs of healthy Humboldt penguins was also assessed. A trial was then conducted to test whether oral administration of Escherichia coli Nissle, expressing high α-Gal levels, modulates anti-α-Gal immunity in a colony of Humboldt penguins. Animals in the vaccination and placebo groups were evaluated before the trial and followed for one year for aspergillosis detection using a diagnostic panel including computed tomography scans, capillary zone electrophoresis, 3-hydroxybutyrate levels, and anti-A. fumigatus Abs. Anti-α-Gal Abs were detected in sera (IgM and IgY) and eggs (IgY) of healthy penguins. Microbiota analysis and functional predictions revealed the presence of α1,3GT genes in the microbiota of Humboldt penguins and other penguin species. A strong decrease in anti-α-Gal IgM levels was observed in all animals in the placebo group three months after vaccination protocol. This decrease was not observed in E. coli Nissle-treated penguins. After the vaccination protocol, we found a positive correlation between anti-E. coli IgY and anti-α-Gal IgY in the E. coli Nissle group, suggesting a correlation between the presence of the bacteria and these Abs. During the study period, three penguins exhibited respiratory signs consistent with aspergillosis. Two were from the placebo group whose symptoms resolved with specific treatments, while a single vaccinated individual developed fatal respiratory aspergillosis eight months after the trial. We conclude that E. coli Nissle represents a safe potential probiotic with a protective effect against aspergillosis in Humboldt penguins that deserves to be further explored for therapeutic uses in these animals.

Cell Autonomous Circadian Systems and Their Relation to Inflammation

All living beings on earth have an important mechanism of 24-h periodicity, which controls their physiology, metabolism, and behavior. In humans, 24-h periodicity is regulated by the superchiasmatic nucleus (SCN) through external and environmental cues. Peripheral organs demonstrate circadian rhythms and circadian clock functions, and these are also observed in cultured cell lines. Every cell contains a CLOCK: BMAL1 loop for the generation of circadian rhythms. In this review, we focused on cell autonomous circadian rhythms in immune cells, the inflammatory diseases caused by disruption of circadian rhythms in hormones, and the role of clock genes in inflammatory diseases.

Transthyretin increases migration and invasion of rat placental trophoblast cells

Preeclampsia (PE) is a hypertensive disorder of pregnancy. Early diagnosis of PE is currently contingent on regular prenatal physical examinations and may be facilitated by identification of novel diagnostic markers. Transthyretin (TTR), also known as prealbumin, is primarily responsible for maintaining the normal levels of thyroxine and retinol binding protein. The expression of TTR is lower in patients with severe PE as compared with healthy controls. Here, we examined the suitability of TTR as a diagnostic marker in pregnant hypertensive rats. N'-nitro-l-arginine-methylesterhydrochloride (l-NAME) was used to generate a rat model of hypertension during pregnancy. Rat placental trophoblast cells were divided into control and TTR groups for in vitro experiments. Systolic blood pressure, diastolic blood pressure, mean blood pressure and urinary protein of hypertensive pregnant rats were higher than those of healthy pregnant rats, but these effects could be reversed by TTR treatment. There were no significant changes in blood pressure and urinary protein in healthy pregnant rats before or after TTR treatment. TTR levels in the serum and placental tissues of pregnant hypertensive rats were significantly reduced compared with those of healthy pregnant rats. Changes in placental and fetal weights in the hypertensive model could also be rescued by TTR treatment. TTR treatment significantly increased the level of matrix metalloproteinase-2/9 in hypertensive rats. Finally, in vivo and in vitro experiments demonstrated that TTR effectively increased the migration and invasion of rat placental trophoblast cells, as well as matrix metalloproteinase-2/9 levels in these cells. In conclusion, our data from a rat model suggest that TTR may have potential as a novel marker for PE diagnosis.

Serum proteome mapping of EGF transgenic mice reveal mechanistic biomarkers of lung cancer precursor lesions with clinical significance for human adenocarcinomas

Atypical adenomatous hyperplasia (AAH) of the lung is a pre-invasive lesion (PL) with high risk of progression to lung cancer (LC). However, the pathways involved are uncertain. We searched for novel mechanistic biomarkers of AAH in an EGF transgenic disease model of lung cancer. Disease regulated proteins were validated by Western immunoblotting and immunohistochemistry (IHC) of control and morphologically altered respiratory epithelium. Translational work involved clinical resection material. Collectively, 68 unique serum proteins were identified by 2DE-MALDI-TOF mass spectrometry and 13 reached statistical significance (p < 0.05). EGF, amphiregulin and the EGFR endosomal sorting protein VPS28 were induced up to 5-fold while IHC confirmed strong induction of these proteins. Furthermore, ApoA1, α-2-macroglobulin, and vitamin-D binding protein were nearly 6- and 2-fold upregulated in AAH; however, ApoA1 was oppositely regulated in LC to evidence disease stage dependent regulation of this tumour suppressor. Conversely, plasminogen and transthyretin were highly significantly repressed by 3- and 20-fold. IHC confirmed induced ApoA1, Fetuin-B and transthyretin expression to influence calcification, inflammation and tumour-infiltrating macrophages. Moreover, serum ApoA4, ApoH and ApoM were 2-, 2- and 6-fold repressed; however tissue ApoM and sphingosine-1-phosphate receptor expression was markedly induced to suggest a critical role of sphingosine-1-phosphate signalling in PL and malignant transformation. Finally, a comparison of three different LC models revealed common and unique serum biomarkers mechanistically linked to EGFR, cMyc and cRaf signalling. Their validation by IHC on clinical resection material established relevance for distinct human lung pathologies. In conclusion, we identified mechanistic biomarker candidates recommended for in-depth clinical evaluation.

In silico analysis and in vivo tests of the tuna dark muscle hydrolysate anti-oxidation effect

Hydrolysate is a mixture of various peptides with specific functions. However, functional identification of hydrolysate with high throughput is still a difficult task. Furthermore, using in vivo tests via animal or cell experiments is time and labor-intensive. In this study, the peptides component of hydrolysate derived from the tuna dark muscle was measured via MALDI-TOF/TOF-MS, and the functions of the KEFT (Lys-Glu-Phe-Thr), EEASA (Glu-Glu-Ala-Ser-Ala) and RYDD (Arg-Tyr-Asp-Asp) peptides, which were found with the highest proportion, were predicted via Discovery Studio 2016 software. All three peptides were predicted to bind to the Keap1 protein with the highest fit-value and to affect the activity of Keap1, which is involved in anti-oxidation pathways. Subsequently, mice experiments showed that administration of tuna dark muscle hydrolysate increased the levels of superoxide dismutase and glutathione peroxidase in the serum and liver (P < 0.05) and decreased the malondialdehyde level (P < 0.05) as well as transcription of Keap1 (P > 0.05), which are consistent with the in silico analysis results using Discovery Studio 2016 software. The combination of in silico analysis and in vivo tests provided an alternative strategy for identifying hydrolysate function and provided insight into high-value utilization of protein hydrolysate.

In silico prediction and in vivo confirmation of anti-oxidation effect.

Inflammatory state exists in familial amyloid polyneuropathy that may be triggered by mutated transthyretin

The relationship between familial amyloid polyneuropathy (FAP), which is caused by mutated transthyretin (TTR), and inflammation has only recently been noted. To determine whether inflammation is present in FAP carriers and patients, serum interleukin (IL)−6 concentration in 57 healthy donors (HD), 21 FAP carriers, and 66 FAP patients was examined, with the relationship between IL-6 and TTR assessed in each group by multiple regression analysis and structural equation models (SEM). Compared with HD, IL-6 concentration was elevated in FAP carriers (p = 0.001, 95% CI 0.398–1.571) and patients (p = 0.002, 95% CI 0.362–1.521). Further, SEM indicated a positive relationship between IL-6 and TTR in FAP carriers (p = 0.010, 95% CI 0.019–0.140), but not in HD and FAP patients. In addition, we determined whether TTR induces production of pro-inflammatory cytokines ex vivo. HD-derived CD14 + monocytes and induced pluripotent stem cell-derived myeloid lineage cells from a HD and FAP patient dose-dependently produced IL-6 under mutated and aggregated TTR conditions, compared with wild-type TTR. In conclusion, FAP carriers and patients are in an inflammatory state, with the presence of mutated TTR being a trigger of inflammation, especially in FAP carriers.

Double-Edged Sword: Musculoskeletal Infection Provoked Acute Phase Response in Children

The acute phase response has a crucial role in mounting the body's response to tissue injury. Excessive activation of the acute phase response is responsible for many complications that occur in orthopedic patients. Given that infection may be considered continuous tissue injury that persistently activates the acute phase response, children with musculoskeletal infections are at markedly increased risk for serious complications. Future strategies that modulate the acute phase response have the potential to improve treatment and prevent complications associated with musculoskeletal infection.

Neuroprotective mechanisms activated in non-seizing rats exposed to sarin

Exposure to organophosphate (OP) nerve agents, such as sarin, may lead to uncontrolled seizures and irreversible brain injury and neuropathology. In rat studies, a median lethal dose of sarin leads to approximately half of the animals developing seizures. Whereas previous studies analyzed transcriptomic effects associated with seizing sarin-exposed rats, our study focused on the cohort of sarin-exposed rats that did not develop seizures. We analyzed the genomic changes occurring in sarin-exposed, non-seizing rats and compared differentially expressed genes and pathway activation to those of seizing rats. At the earliest time point (0.25 h) and in multiple sarin-sensitive brain regions, defense response genes were commonly expressed in both groups of animals as compared to the control groups. All sarin-exposed animals activated the MAPK signaling pathway, but only the seizing rats activated the apoptotic-associated JNK and p38 MAPK signaling sub-pathway. A unique phenotype of the non-seizing rats was the altered expression levels of genes that generally suppress inflammation or apoptosis. Importantly, the early transcriptional response for inflammation- and apoptosis-related genes in the thalamus showed opposite trends, with significantly down-regulated genes being up-regulated, and vice versa, between the seizing and non-seizing rats. These observations lend support to the hypothesis that regulation of anti-inflammatory genes might be part of an active and sufficient response in the non-seizing group to protect against the onset of seizures. As such, stimulating or activating these responses via pretreatment strategies could boost resilience against nerve agent exposures.

Comparative Proteomics of Sera From HCC Patients With Different Origins

BACKGROUND

Hepatocellular carcinoma (HCC), a major fatal cancer worldwide, is induced by different etiological factors in the liver.

OBJECTIVES

To gain insight into serum protein profiling of HCC with different etiologies.

PATIENTS AND METHODS

We subjected the sera of HBV-HCC, HCV-HCC, non-B non-C-HCC patients, and healthy volunteers to two-dimensional gel electrophoresis (2-DE) and liquid chromatography tandem mass spectrometry (LC-MS/MS).

RESULTS

We found 30 differentially expressed protein spots (≥ 1.5 fold P < 0.05) between these two analyses; of them 17 protein spots corresponding to 8 proteins were identified by MS. Transthyretin, leucine rich α-2-glycoprotein, and ficolin 3 were differentially expressed between HBV-related HCC and non-B non-C-HCC sera. Moreover, haptoglobin α-2 isoforms were decreased in HCV-HCC compared to non-B non-CHCC.

CONCLUSIONS

Serum proteome analyses of HCC with different origins showed a differential protein pattern, presumably related to different hepatopathogenesis in liver induced by different agents. Further studies are required to clarify the importance of identified proteins for early diagnosis of HCC with different origins.

Modifications in rat plasma proteome after remote ischemic preconditioning (RIPC) stimulus: identification by a SELDI-TOF-MS approach

Remote ischemic preconditioning’s (RIPC) ability to render the myocardium resistant to subsequent prolonged ischemia is now clearly established in different species, including humans. Strong evidence suggests that circulating humoral mediators play a key role in signal transduction, but their identities still need to be established. Our study sought to identify potential circulating RIPC mediators using a proteomic approach. Rats were exposed to 10-min limb ischemia followed by 5- (RIPC 5′) or 10-min (RIPC 10′) reperfusion prior to blood sampling. The control group only underwent blood sampling. Plasma samples were isolated for proteomic analysis using surface-enhanced laser desorption and ionization - time of flight - mass spectrometry (SELDI-TOF-MS). A total of seven proteins, including haptoglobin and transthyretin, were detected as up- or down-regulated in response to RIPC. These proteins had previously been identified as associated with organ protection, anti-inflammation, and various cellular and molecular responses to ischemia. In conclusion, this study indicates that RIPC results in significant modulations of plasma proteome.

Differentially Expressed Proteins in Chronic Active Hepatitis, Cirrhosis, and HCC Related to HCV Infection in Comparison With HBV Infection: A proteomics study

BACKGROUND

Hepatocellular carcinoma is a highly progressive cancer in the case of late diagnosis which is frequently associated with HBV and HCV viral infections.

OBJECTIVES

To identify differentially expressed serum proteins among three main stages of HCV infection and healthy individuals, and their comparisons with sera from patients with the same stage of HBV infection.

PATIENTS AND METHODS

Two-dimensional polyacrylamide gel electrophoresis combined with liquid chromatography-tandem mass spectrometry was performed on 47 sera from healthy volunteers, those with chronic active hepatitis, cirrhosis and HCC patients associated with HBV and HCV infections.

RESULTS

Among these, 62 spots were differentially expressed (≥ 1.5 fold; P < 0.05), of which 42 spots that corresponded to 15 proteins were identified by liquid chromatography-tandem mass spectrometry. CD5-like antigen (CD5L) was differentially expressed between cirrhosis and HCC patients with HCV infection. Leucine-rich α2-glycoprotein (LRG) and haptoglobin (HP) α2 isoforms differed in the HCC that was associated with either HCV or HBV infections.

CONCLUSIONS

CD5L might be a useful biomarker for early diagnosis of HCC in HCV cirrhotic patients. LRG and HP α2 isoforms could be potential markers for distinguishing viral HCC. Our results also further support the presence of varying molecules involved in hepatocarcinogenesis in HBV when compared with HCV infection.

Two-dimensional difference gel electrophoresis (DIGE) analysis of sera from visceral leishmaniasis patients

Introduction

Visceral leishmaniasis is a parasitic infection caused by Lesihmania donovani complex and transmitted by the bite of the phlebotomine sand fly. It is an endemic disease in many developing countries with more than 90% of the cases occurring in Bangladesh, India, Nepal, Sudan, Ethiopia and Brazil. The disease is fatal if untreated. The disease is conventionally diagnosed by demonstrating the intracellular parasite in bone marrow or splenic aspirates. This study was carried out to discover differentially expressed proteins which could be potential biomarkers.

Methods

Sera from six visceral leishmaniasis patients and six healthy controls were depleted of high abundant proteins by immunodepletion. The depleted sera were compared by 2-D Difference in gel electrophoresis (DIGE). Differentially expressed proteins were identified the by tandem mass spectrometry. Three of the identified proteins were further validated by western blotting.

Results

This is the first report of serum proteomics study using quantitative Difference in gel electrophoresis (DIGE) in visceral leishmaniasis. We identified alpha-1-acidglycoprotein and C1 inhibitor as up regulated and transthyretin, retinol binding protein and apolipoprotein A-I as down regulated proteins in visceral leishmaniasis sera in comparison with healthy controls. Western blot validation of C1 inhibitor, transthyretin and apolipoprotein A-I in a larger cohort (n = 29) confirmed significant difference in the expression levels (p < 0.05).

Conclusions

In conclusion, DIGE based proteomic analysis showed that several proteins are differentially expressed in the sera of visceral leishmaniasis. The five proteins identified here have potential, either independently or in combination, as prognostic biomarkers.

Two-dimensional difference gel electrophoresis (DiGE) analysis of plasmas from dengue fever patients

Dengue fever is the world's most important arthropod-born viral disease affecting humans. To contribute to a better understanding of its pathogenesis, this study aims to identify proteins differentially expressed in plasmas from severe dengue fever patients relative to healthy donors. The use of 2-D Fluorescence Difference Gel Electrophoresis to analyze plasmas depleted of six high-abundance proteins (albumin, IgG, antitrypsin, IgA, transferrin and haptoglobin) allowed for the detection of 73 differentially expressed protein spots (n = 13, p < 0.01), of which 37 could be identified by mass spectrometry. These 37 spots comprised a total of 14 proteins, as follows: 7 had increased expression in plasmas from dengue fever patients (C1 inhibitor, alpha1-antichymotrypsin, vitamin D-binding protein, fibrinogen gamma-chain, alpha1-acid glycoprotein, apolipoprotein J and complement component C3c), while 7 others had decreased expression in the same samples (alpha-2 macroglobulin, prothrombin, histidine-rich glycoprotein, apolipoproteins A-IV and A-I, transthyretin and complement component C3b). The possible involvement of these proteins in the inflammatory process triggered by dengue virus infection and in the repair mechanisms of vascular damage occurring in this pathology is discussed in this study.

Activation of Thromboxane Receptor Upregulates Interleukin (IL)-1β–Induced VCAM-1 Expression Through JNK Signaling

Objective— Activation of thromboxane receptors (TPr) is implicated in atherosclerosis and inflammation. This study examined how activation of TPr modulates IL-1β–induced vascular cell adhesion molecule (VCAM)-1 expression in aortic vascular smooth muscle cells (VSMCs).

Methods and Results— In VSMCs, activation of TPr with U46619, a stable thromboxane A 2 mimetic, alone did not induce VCAM-1 expression, but enhanced that caused by IL-1β. The enhancement of VCAM-1 expression caused by U46619 occurred at the transcriptional level and was inhibited either by SP600125, a c-Jun N-terminal kinase (JNK) inhibitor, or by overexpression of a dominant-negative JNK1, but not by SB203580, a p38 mitogen-activated protein kinase inhibitor. The activation of JNK by U46619 resulted in enhanced phosphorylation and nuclear translocation of c-Jun associated with an enhanced activation of activator protein (AP)-1, which were abolished by SQ29548, a TPr antagonist, or the JNK inhibitor. Treatment of the cells with U46619 alone did not induce NF-κB activation. Furthermore, U46619 enhanced IL-1β–induced THP-1 monocyte binding to VSMCs, which was inhibited by SQ29548 or SP600125.

Conclusion— This study demonstrates that activation of TPr upregulates IL-1β–induced VCAM-1 expression by enhancing the activation of JNK pathway that leads to enhanced AP-1 activation.

The choroid plexus response to peripheral inflammatory stimulus

Increased interest is being raised on the interaction between systemic inflammation and the brain. The choroid plexus (CP) constitutes a monolayer of epithelial cells located within the brain ventricles and is responsible for the production of cerebrospinal fluid (CSF). Despite the knowledge that the CP capillaries are fenestrated, allowing free passage of molecules and cells, the involvement of the vast blood-brain boundary represented by the CP/CSF barrier in brain inflammatory processes has seldom been considered. In the present study we investigate, in mice, how the expression of genes encoding major constitutively expressed CP proteins is influenced by a systemic inflammatory stimulus. Confirming that the CP responds to peripheral inflammation, the messenger RNA (mRNA) levels of the pro-inflammatory cytokines interleukin 1 beta and tumor necrosis factor alpha are rapidly induced. As for the constitutively expressed proteins, while the mRNA for genes encoding transthyretin and transferrin remain unaltered by the inflammatory challenge, that for prostaglandin D2 synthase (LPTGDS) is up-regulated at 6 h, and stays up-regulated up to 24 h after lipopolysacharide administration. Accordingly, LPTGDS CSF levels are also augmented. LPTGDS catalyzes the synthesis of the major prostanoid of the CNS and, being increased in the CSF, might mediate immune signaling into the brain. These observations emphasize that the CP must be considered a relevant mediator of immune signals between the periphery and the brain.

The circadian clock Period 2 gene regulates gamma interferon production of NK cells in host response to lipopolysaccharide-induced endotoxic shock

The Period 2 (Per2) gene is a key molecular component in controlling mammalian circadian rhythms at the levels of gene expression, physiology, and pathogenesis. Although many immune parameters, such as the number of different subtypes of circulating immune cells and the level of cytokine production in response to infection with bacteria and viruses, have been well documented to display a circadian pattern in mammals, the basic features of molecular clock components in the immune system and the role of clock genes in regulating host immune defenses remain uncharacterized. Previously, we have reported that circadian clock genes oscillate in human mononuclear cells. Here we report that Per2-deficient mice were more resistant to lipopolysaccharide (LPS)-induced endotoxic shock than control wild-type mice. We further demonstrate that the levels of the proinflammatory cytokines gamma interferon (IFN-gamma) and interleukin-1beta (IL-1beta) in the serum were dramatically decreased in Per2-/- mice following LPS challenge, while production of tumor necrosis factor alpha, IL-6, and IL-10 was approximately normal, compared to that in control wild-type mice. Flow cytometric analyses confirmed that the cellularity of most of the immune cell subsets in the spleens of LPS-challenged mice was normal and that the impaired IFN-gamma production in Per2-/- mice was attributable to defective NK and NKT cell function. Our data suggest that Per2 is an important regulator of NK cell function, therefore providing the first direct link between the circadian clock system and innate immune responses.

Identification of a novel apolipoprotein, ApoN, in ovarian follicular fluid

A novel apolipoprotein, designated ApoN, has been identified in bovine ovarian follicular fluid using chromatographic purification methods, amino acid sequence analysis, molecular biology, and bioinformatics. The apolipoprotein is a hydrophobic 12-kDa protein processed from the C terminus of a 29-kDa precursor expressed in a number of tissues, including the ovary, testis, the anterior chamber of the eye, skeletal muscle, uterus, and liver. Bovine, porcine, and murine ApoN display significant homology at the amino acid level across the entire precursor sequence. Surprisingly, there appears to be no orthologous protein in the human, although an APON-like pseudogene is found on chromosome 12. The N-terminal fragment of the ApoN precursor shows significant homology with the N-terminal sequence of the precursor of the cholesterol transport regulatory protein ApoF, but the corresponding C-terminal sequences of ApoN and ApoF possess no homology. ApoN is present in the high-density lipoprotein fraction of bovine serum and both the high-density lipoprotein and low-density lipoprotein fractions of bovine follicular fluid and is found in several tissues that are associated with local immunological privilege. These data suggest that ApoN may play a role in steroidogenesis and/or immunoregulation in the gonads of nonhuman species, as well as similar roles in other tissues.

Combined proteomic approach with SELDI-TOF-MS and peptide mass fingerprinting identified the rapid increase of monomeric transthyretin in rat cerebrospinal fluid after transient focal cerebral ischemia

Several proteins are known to be markedly expressed in the brain during cerebral ischemia, however the change in protein profiles within the cerebrospinal fluid (CSF) after an ischemic insult has not been fully elucidated. We studied the changes in the CSF proteome in rat transient middle cerebral artery occlusion model. Surface enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectrometry (MS) was used to detect the time-course changes in CSF protein patterns after transient focal brain ischemia. According to hierarchical cluster analysis by self-organising tree algorism (SOTA), the temporal pattern of protein peaks was divided into four groups: acute increase group, chronic increase group, gradual decrease group and unchanged group. In the acute increase group, the expression of a 13.6-kDa protein was markedly increased during the acute phase. The 13.6-kDa protein was identified as monomeric form of transthyretin using two-dimensional electrophoresis and peptide mass fingerprinting based on matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The monomeric transthyretin may represent an ischemia-specific CSF marker to indicate the sequential changes according to ischemic insults of the brain.

Transthyretin as a thyroid hormone carrier: function revisited

Thyroid hormones are essential for normal mammalian development and for normal metabolism. Thyroxine (T4) is the principal product synthesized by the thyroid follicles, and triiodothyronine (T3), the biologically active hormone, derives mainly from tissue T4 deiodination. More than 99% of the circulating hormone is bound to plasma proteins, mainly to thyroxine-binding globulin, transthyretin and albumin in man, and to transthyretin and albumin in rodents. The role of plasma proteins in the transport of hormones to target tissues has, for a long time, been controversial. The liver and the choroid plexus are the major sites of transthyretin synthesis, tissues from which transthyretin is secreted into the blood and the cerebrospinal fluid, respectively. Transthyretin has been proposed to mediate thyroid hormone transfer into the tissues, particularly into the brain across the choroid-plexus-cerebrospinal fluid barrier. Studies in a transthyretin-null mice strain have shown conclusively that transthyretin is not indespensable for thyroid hormones' entry into the brain and other tissues, nor for the maintenance of an euthyroid status. An euthyroid status is also observed in man totally deprived of thyroxine-binding globulin and in rats without albumin. Taken together, these results exclude dependence of thyroid hormone homeostasis on any major plasma carrier per se. This evidence agrees with the free hormone hypothesis which states that the biologically significant fraction, that is taken up by the tissues, is the free circulating hormone.

Thromboxane A2 (TXA2) receptor blockade suppresses monocyte chemoattractant protein-1 (MCP-1) expression by stimulated vascular endothelial cells

In a previous study, it was reported that stimulation with a TXA2 receptor agonist, U46619, augments the expression of adhesion molecules by human umbilical vein endothelial cells (HUVEC). In the present study we showed that U46619 augments the expression of MCP-1 in HUVEC, both at the protein and mRNA levels. Pretreatment with TXA2 receptor antagonists greatly diminishes the extent of tumour necrosis factor-alpha (TNF-alpha)-, platelet-activating factor (PAF)-, or U46619-induced mRNA accumulation and production of MCP-1. Protein kinase C (PKC) inhibitors diminish U46619-induced mRNA accumulation and production of MCP-1. NAC, which inhibits nuclear factor kappaB (NF-kappaB) activation and activating protein 1 (AP-1) binding activity, inhibits the expression of MCP-1 at the protein and mRNA levels. These results indicate that in HUVEC stimulation via the TXA2 receptors augments MCP-1 production by induction of the NF-kappaB and AP-1 binding activity through the PKC system.