The inter-alpha-inhibitor family: from structure to regulation

Effects of age, experience and inter-alpha inhibitor proteins on working memory and neuronal plasticity after neonatal hypoxia-ischemia

Neonatal cerebral hypoxia-ischemia (HI) commonly results in cognitive and sensory impairments. Early behavioral experience has been suggested to improve cognitive and sensory outcomes in children and animal models with perinatal neuropathology. In parallel, we previously showed that treatment with immunomodulator Inter-alpha Inhibitor Proteins (IAIPs) improves cellular and behavioral outcomes in neonatal HI injured rats. The purpose of the current study was to evaluate the influences of early experience and typical maturation in combination with IAIPs treatment on spatial working and reference memory after neonatal HI injury. A second aim was to determine the effects of these variables on hippocampal CA1 neuronal morphology. Subjects were divided into two groups that differed with respect to the time when exposed to eight arm radial water maze testing: Group one was tested as juveniles (early experience, Postnatal day (P) 36-61) and adults (P88-113), and Group two was tested in adulthood only (P88-113; without early experience). Three treatment conditions were included in each experience group (HI+Vehicle, HI+IAIPs, and Sham subjects). Incorrect arm entries (errors) were compared between treatment and experience groups across three error types (reference memory (RM), working memory incorrect (WMI), working memory correct (WMC)). Early experience led to improved working memory performance regardless of treatment. Combining IAIPs intervention with early experience provided a long-term behavioral advantage on the WMI component of the task in HI animals. Anatomically, early experience led to a decrease in the average number of basal dendrites per CA1 pyramidal neuron for IAIP treated subjects and a significant reduction in basal dendritic length in control subjects, highlighting the importance of pruning in typical early life learning. Our results support the hypothesis that early behavioral experience combined with IAIPs improve outcome on a relativity demanding cognitive task, beyond that of a single intervention strategy, and appears to facilitate neuronal plasticity following neonatal brain injury.

Niche Regulation of Limbal Epithelial Stem Cells: Relationship between Inflammation and Regeneration

Human limbal palisades of Vogt are the ideal site for studying and practicing regenerative medicine due to their accessibility. Nonresolving inflammation in limbal stroma is common manifestation of limbal stem cell (SC) deficiency and presents as a threat to the success of transplanted limbal epithelial SCs. This pathologic process can be overcome by transplantation of cryopreserved human amniotic membrane (AM), which exerts anti-inflammatory, antiscarring and anti-angiogenic action to promote wound healing. To determine how AM might exert anti-inflammation and promote regeneration, we have purified a novel matrix, HC-HA/PTX3, responsible for the efficacy of AM efficacy. HC-HA complex is covalently formed by hyaluronan (HA) and heavy chain 1 (HC1) of inter-α-trypsin inhibitor by the catalytic action of tumor necrosis factor-stimulated gene-6 (TSG-6) and are tightly associated with pentraxin 3 (PTX3) to form HC-HA/PTX3. In vitro reconstitution of the limbal niche can be established by reunion between limbal epithelial progenitors and limbal niche cells on different substrates. In 3-dimensional Matrigel, clonal expansion indicative of SC renewal is correlated with activation of canonical Wnt signaling and suppression of canonical bone morphogenetic protein (BMP) signaling. In contrast, SC quiescence can be achieved in HC-HA/PTX3 by activation of canonical BMP signaling and non-canonical planar cell polarity (PCP) Wnt signaling, but suppression of canonical Wnt signaling. HC-HA/PTX3 is a novel matrix mitigating nonresolving inflammation and restoring SC quiescence in the niche for various applications in regenerative medicine.

Positive Mode LC-MS/MS Analysis of Chondroitin Sulfate Modified Glycopeptides Derived from Light and Heavy Chains of The Human Inter-α-Trypsin Inhibitor Complex

The inter-α-trypsin inhibitor complex is a macromolecular arrangement of structurally related heavy chain proteins covalently cross-linked to the chondroitin sulfate (CS) chain of the proteoglycan bikunin. The inter-α-trypsin inhibitor complex is abundant in plasma and associated with inflammation, kidney diseases, cancer and diabetes. Bikunin is modified at Ser-10 by a single low-sulfated CS chain of 23-55 monosaccharides with 4-9 sulfate groups. The innermost four monosaccharides (GlcAβ3Galβ3Galβ4Xylβ-O-) compose the linkage region, believed to be uniform with a 4-O-sulfation to the outer Gal. The cross-linkage region of the bikunin CS chain is located in the nonsulfated nonreducing end, (GalNAcβ4GlcAβ3)(n), to which heavy chains (H1-H3) may be bound in GalNAc to Asp ester linkages. In this study we employed a glycoproteomics protocol to enrich and analyze light and heavy chain linkage and cross-linkage region CS glycopeptides derived from the IαI complex of human plasma, urine and cerebrospinal fluid samples. The samples were trypsinized, enriched by strong anion exchange chromatography, partially depolymerized with chondroitinase ABC and analyzed by LC-MS/MS using higher-energy collisional dissociation. The analyses demonstrated that the CS linkage region of bikunin is highly heterogeneous. In addition to sulfation of the Gal residue, Xyl phosphorylation was observed although exclusively in urinary samples. We also identified novel Neu5Ac and Fuc modifications of the linkage region as well as the presence of mono- and disialylated core 1 O-linked glycans on Thr-17. Heavy chains H1 and H2 were identified cross-linked to GalNAc residues one or two GlcA residues apart and H1 was found linked to either the terminal or subterminal GalNAc residues. The fragmentation behavior of CS glycopeptides under variable higher-energy collisional dissociation conditions displays an energy dependence that may be used to obtain complementary structural details. Finally, we show that the analysis of sodium adducts provides confirmatory information about the positions of glycan substituents.

Hyaluronan cable formation by ocular trabecular meshwork cells

Hyaluronan (HA) in the ocular trabecular meshwork (TM) is a critical modulator of aqueous humor outflow. Individual HA strands in the pericellular matrix can coalesce to form cable-like structures, which have different functional properties. Here, we investigated HA structural configuration by TM cells in response to various stimuli known to stimulate extracellular matrix (ECM) remodeling. In addition, the effects of HA cable induction on aqueous outflow resistance was determined. Primary TM cell cultures grown on tissue culture-treated plastic were treated for 12-48 h with TNFα, IL-1α, or TGFβ2. TM cells grown on silicone membranes were subject to mechanical stretch, which induces synthesis and activation of ECM proteolytic enzymes. HA structural configuration was investigated by HA binding protein (HAbp) staining and confocal microscopy. HAbp-labeled cables were induced by TNFα, TGFβ2 and mechanical stretch, but not by IL-1α. HA synthase (HAS) gene expression was quantitated by quantitative RT-PCR and HA concentration was measured by ELISA assay. By quantitative RT-PCR, HAS-1, -2, and -3 genes were differentially up-regulated and showed temporal differences in response to each treatment. HA concentration was increased in the media by TNFα, TGFβ2 and IL-1α, but mechanical stretch decreased pericellular HA concentrations. Immunofluorescence and Western immunoblotting were used to investigate the distribution and protein levels of the HA-binding proteins, tumor necrosis factor-stimulated gene-6 (TSG-6) and inter-α-inhibitor (IαI). Western immunoblotting showed that TSG-6 and IαI were increased by TNFα, TGFβ2 and IL-1α, but mechanical stretch reduced their levels. The underlying substrate appears to affect the identity of IαI·TSG-6·HA complexes since different complexes were detected when TM cells were grown on a silicone substrate compared to a rigid plastic surface. Porcine anterior segments were perfused with 10 μg/ml polyinosinic:polycytidylic acid (polyI:C), a potent inducer of HA cables, and outflow rates were monitored for 72 h. PolyI:C had no significant effect on outflow resistance in porcine anterior segments perfused at physiological pressure. Collectively, HAS gene expression, HA concentration and configuration are differentially modified in response to several treatments that induce ECM remodeling in TM cells. In ocular TM cells, our data suggests that the most important determinant of HA cable formation appears to be the ratio of HA chains produced by the different HAS genes. However, the act of rearranging pericellular HA into cable-like structures does not appear to influence aqueous outflow resistance.

Ontogeny of inter-alpha inhibitor proteins in ovine brain and somatic tissues

Inter-alpha inhibitor proteins (IAIPs) found in relatively high concentrations in human plasma are important in inflammation. IAIPs attenuate brain damage in young and adult subjects, decrease during sepsis and necrotizing enterocolitis in premature infants, and attenuate sepsis-related inflammation in newborn rats. Although a few studies have reported adult organ-specific IAIP expression, information is not available on age-dependent IAIP expression. Given evidence suggesting IAIPs attenuate brain damage in young and adult subjects, and inflammation in newborns, we examined IAIP expression in plasma, cerebral cortex (CC), choroid plexus (CP), cerebral spinal fluid (CSF), and somatic organs in fetal, newborn, and adult sheep to determine the endogenous expression patterns of these proteins during development. IAIPs (enzyme-linked immunosorbent assay) were higher in newborn and adult than fetal plasma (P < 0.05). Western immunoblot detected 125 kDa PaI (Pre-alpha Inhibitor) and 250 kDa IaI (Inter-alpha Inhibitor) in plasma, CNS, and somatic organs. PaI expression in CC and CP was higher in fetuses than newborns and adults, but IaI expression was higher in adults than fetuses and newborns. Both PaI and IaI were higher in fetal than newborn CSF. IAIPs exhibited organ-specific ontogenic patterns in placenta, liver, heart, and kidney. These results provide evidence for the first time that plasma, brain, placenta, liver, heart, and kidney express IAIPs throughout ovine development and that expression patterns are unique to each organ. Although exact functions of IAIPs in CNS and somatic tissues are not known, their presence in relatively high amounts during development suggests their potential importance in brain and organ development.

Inter-α-trypsin inhibitor heavy chain 5 (ITIH5) is overexpressed in inflammatory skin diseases and affects epidermal morphology in constitutive knockout mice and murine 3D skin models

Inter-α-trypsin inhibitors are protease inhibitors that are thought to be important regulators in various acute-phase processes. They are composed of one light chain (bikunin) and different heavy chains (ITIHs). The only function known so far of ITIHs is the covalent linkage to hyaluronan (HA). As there is virtually no knowledge on the distribution and function of ITIH proteins in skin tissue, we performed a systematic characterization of ITIH expression in healthy and diseased skin. Using GeneChip(®) Human Exon 1.0 ST expression profiling, we found that ITIH5 represents the major ITIH family member expressed in human skin. Moreover, the use of quantitative reverse transcription PCR and a customized ITIH5-specific antibody indicated that ITIH5 is predominantly produced by dermal fibroblasts. Immunohistochemical analysis revealed a clearly detectable ITIH5 protein expression in normal skin. Interestingly, ITIH5 expression was significantly up-regulated in inflammatory skin diseases. Furthermore, 3D skin models employing murine Itih5(-/-) epidermal keratinocytes and dermal fibroblasts as well as skin specimens of Itih5(-/-) mice revealed a significantly altered epidermal structure compared to wild-type controls. Hence, we can strengthen the presumption that ITIH5 may constitute a novel regulatory molecule of the human skin that could play an important role in inflammation via its interaction with HA.

Inter-α inhibitor protein and its associated glycosaminoglycans protect against histone-induced injury

Extracellular histones are mediators of tissue injury and organ dysfunction; therefore they constitute potential therapeutic targets in sepsis, inflammation, and thrombosis. Histone cytotoxicity in vitro decreases in the presence of plasma. Here, we demonstrate that plasma inter-α inhibitor protein (IAIP) neutralizes the cytotoxic effects of histones and decreases histone-induced platelet aggregation. These effects are mediated through the negatively charged glycosaminoglycans (GAGs) chondroitin sulfate and high-molecular-weight hyaluronan (HMW-HA) associated with IAIP. Cell surface anionic glycosaminoglycans heparan sulfate and HA protect the cells against histone-mediated damage in vitro. Surface plasmon resonance showed that both IAIP and HMW-HA directly bind to recombinant histone H4. In vivo neutralization of histones with IAIP and HMW-HA prevented histone-induced thrombocytopenia, bleeding, and lung microvascular thrombosis, decreased neutrophil activation, and averted histone-induced production of inflammatory cytokines and chemokines. IAIP and HMW-HA colocalized with histones in necrotic tissues and areas that displayed neutrophil extracellular traps. Increasing amounts of IAIP-histone complexes detected in the plasma of septic baboons correlated with increase in histones and/or nucleosomes and consumption of plasma IAIP. Our data suggest that IAIP, chondroitin sulfate, and HMW-HA are potential therapeutic agents to protect against histone-induced cytotoxicity, coagulopathy, systemic inflammation, and organ damage during inflammatory conditions such as sepsis and trauma.

Incorporation of pentraxin 3 into hyaluronan matrices is tightly regulated and promotes matrix cross-linking

Mammalian oocytes are surrounded by a highly hydrated hyaluronan (HA)-rich extracellular matrix with embedded cumulus cells, forming the cumulus cell·oocyte complex (COC) matrix. The correct assembly, stability, and mechanical properties of this matrix, which are crucial for successful ovulation, transport of the COC to the oviduct, and its fertilization, depend on the interaction between HA and specific HA-organizing proteins. Although the proteins inter-α-inhibitor (IαI), pentraxin 3 (PTX3), and TNF-stimulated gene-6 (TSG-6) have been identified as being critical for COC matrix formation, its supramolecular organization and the molecular mechanism of COC matrix stabilization remain unknown. Here we used films of end-grafted HA as a model system to investigate the molecular interactions involved in the formation and stabilization of HA matrices containing TSG-6, IαI, and PTX3. We found that PTX3 binds neither to HA alone nor to HA films containing TSG-6. This long pentraxin also failed to bind to products of the interaction between IαI, TSG-6, and HA, among which are the covalent heavy chain (HC)·HA and HC·TSG-6 complexes, despite the fact that both IαI and TSG-6 are ligands of PTX3. Interestingly, prior encounter with IαI was required for effective incorporation of PTX3 into TSG-6-loaded HA films. Moreover, we demonstrated that this ternary protein mixture made of IαI, PTX3, and TSG-6 is sufficient to promote formation of a stable (i.e. cross-linked) yet highly hydrated HA matrix. We propose that this mechanism is essential for correct assembly of the COC matrix and may also have general implications in other inflammatory processes that are associated with HA cross-linking.

Effects of inter-alpha inhibitor proteins on neonatal brain injury: Age, task and treatment dependent neurobehavioral outcomes

Hypoxic-ischemic (HI) brain injury is frequently associated with premature and/or full term birth related complications. HI injury often results in learning and processing deficits that reflect widespread damage to an extensive range of cortical and sub-cortical brain structures. Further, inflammation has been implicated in the long-term progression and severity of HI injury. Recently, inter-alpha inhibitor proteins (IAIPs) have been shown to attenuate inflammation in models of systemic infection. Importantly, preclinical studies of neonatal HI injury and neuroprotection often focus on single time windows of assessment or single behavioral domains. This approach limits translational validity, given evidence for a diverse spectrum of neurobehavioral deficits that may change across developmental windows following neonatal brain injury. Therefore, the aims of this research were to assess the effects of human IAIPs on early neocortical cell death (72h post-insult), adult regional brain volume measurements (cerebral cortex, hippocampus, striatum, corpus callosum) and long-term behavioral outcomes in juvenile (P38-50) and adult (P80+) periods across two independent learning domains (spatial and non-spatial learning), after postnatal day 7 HI injury in rats. Here, for the first time, we show that IAIPs reduce acute neocortical neuronal cell death and improve brain weight outcome 72h following HI injury in the neonatal rat. Further, these longitudinal studies are the first to show age, task and treatment dependent improvements in behavioral outcome for both spatial and non-spatial learning following systemic administration of IAIPs in neonatal HI injured rats. Finally, results also show sparing of brain regions critical for spatial and non-spatial learning in adult animals treated with IAIPs at the time of injury onset. These data support the proposal that inter-alpha inhibitor proteins may serve as novel therapeutics for brain injury associated with premature birth and/or neonatal brain injury and highlight the importance of assessing multiple ages, brain regions and behavioral domains when investigating experimental treatment efficacy.

Site-specific glycan microheterogeneity of inter-alpha-trypsin inhibitor heavy chain H4

Inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4) is a 120 kDa acute-phase glycoprotein produced primarily in the liver, secreted into the blood, and identified in serum. ITIH4 is involved in liver development and stabilization of the extracellular matrix (ECM), and its expression is altered in liver disease. In this study, we aimed to characterize glycosylation of recombinant and serum-derived ITIH4 using analytical mass spectrometry. Recombinant ITIH4 was analyzed to optimize glycopeptide analyses, followed by serum-derived ITIH4. First, we confirmed that the four ITIH4 N-X-S/T sequons (N81, N207, N517, and N577) were glycosylated by treating ITIH4 tryptic/GluC glycopeptides with PNGaseF in the presence of (18)O water. Next, we performed glycosidase-assisted LC-MS/MS analysis of ITIH4 trypsin-GluC glycopeptides enriched via hydrophilic interaction liquid chromatography to characterize ITIH4 N-glycoforms. While microheterogeneity of N-glycoforms differed between ITIH4 protein expressed in HEK293 cells and protein isolated from serum, occupancy of N-glycosylation sites did not differ. A fifth N-glycosylation site was discovered at N274 with the rare nonconsensus NVV motif. Site N274 contained high-mannose N-linked glycans in both serum and recombinant ITIH4. We also identified isoform-specific ITIH4 O-glycoforms and documented that utilization of O-glycosylation sites on ITIH4 differed between the cell line and serum.

Enhanced expression of a 35 kDa fragment of inter-alpha-trypsin inhibitor H4 in sera of healthy pregnant women and patients with hydatidiform mole

Background

Accumulated data from previous studies appear to suggest a link between the overexpression of a 35 kDa fragment of serum inter-alpha-trypsin inhibitor H4 (ITIH4) with cancers that are associated with up-regulated levels of oestrogens. The truncated fragment was postulated to be a product of oestrogen-induced action of kallikrein on native ITIH4. The present lectin-based proteomic analyses were performed to assess the specificity of the 35 kDa fragment of ITIH4 as a potential cancer biomarker and determine whether it was also overexpressed in the sera of cancer-negative pregnant women who are known to have high levels of plasma oestrogens.

Results

Our results demonstrated that the 35 kDa fragment of ITIH4 was overexpressed in healthy pregnant women and patients with hydatidiform mole, relative to the controls. The serum oestradiol levels of both groups of pregnant subjects were also confirmed to be higher than those of the control women who were not pregnant.

Conclusions

Overexpression of the 35 kDa fragment of ITIH4 was not restrictive to patients with cancers but also occurred in women who were pregnant and those diagnosed with hydatidiform mole. Our data implicate the limitation of the 35 kDa ITIH4 fragment as a cancer biomarker and its correlation with serum oestrogen levels.

Urine of patients with early prostate cancer contains lower levels of light chain fragments of inter-alpha-trypsin inhibitor and saposin B but increased expression of an inter-alpha-trypsin inhibitor heavy chain 4 fragment

The present study was aimed at the identification of proteins that are differentially expressed in the urine of patients with prostate cancer (PCa), those with benign prostatic hyperplasia (BPH) and age-matched healthy male control subjects. Using a combination of 2DE and MS/MS, significantly lower expression of urinary saposin B and two different fragments of inter-alpha-trypsin inhibitor light chain (ITIL) was demonstrated in the PCa patients compared to the controls. However, only one of the ITIL fragments was significantly different between the PCa and BPH patients. When image analysis was performed on urinary proteins that were transferred onto NC membranes and detected using a lectin that binds to O-glycans, a truncated fragment of inter-alpha-trypsin inhibitor heavy chain 4 was the sole protein found to be significantly enhanced in the PCa patients compared to the controls. Together, these urinary peptide fragments might be useful complementary biomarkers to indicate PCa as well as to distinguish it from BPH, although further epidemiological evidence on the specificity and sensitivity of the protein candidates is required.

Effect of cryopreserved amniotic membrane on the development of adhesions and fibrosis after extraocular muscle surgery in rabbits

PURPOSE

To histopathologically evaluate the effect of cryopreserved human amniotic membrane (AM) transplant on preventing the development of postoperative adhesions after extraocular muscle surgery.

METHODS

Ten albino rabbits were used. The superior rectus muscles were bilaterally resected. In right eyes, the muscle was wrapped with cryopreserved human AM (group AM). In left eyes, the muscle was not wrapped with AM and served as a control group (group C). The rabbits were killed, and the eyes were enucleated 6 weeks after surgery to perform histopathological examination.

RESULTS

On histopathological examination, the AM was present in eight eyes, surrounded by periamniotic inflammation, with no adhesions detected between rectus muscle and sclera, conjunctiva and Tenon's capsule in the segment where the AM was present, but detected elsewhere. Adhesions were detected in the other two eyes of group AM, in which the AM was absent, and in all group C eyes. When comparing eye pairs of each rabbit, AM eyes showed significantly less adhesions between the muscle and sclera (p = 0.009) and between the muscle and Tenon's capsule and conjunctiva (p = 0.008), in the region of AM application, and significantly more foreign body inflammation (p = 0.031), than C eyes. The differences between AM and C eye pairs, in terms of conjunctival inflammation and vascularity and muscle fibrosis, were insignificant (p > 0.05).

CONCLUSIONS

Cryopreserved AM is effective in reducing postoperative extraocular muscle adhesions. Its application is, therefore, recommended during strabismus reoperations.

Irreversible heavy chain transfer to hyaluronan oligosaccharides by tumor necrosis factor-stimulated gene-6

The covalent transfer of heavy chains (HCs) from inter-α-inhibitor (IαI) to hyaluronan (HA) via the protein product of tumor necrosis factor-stimulated gene-6 (TSG-6) forms the HC-HA complex, a pathological form of HA that promotes the adhesion of leukocytes to HA matrices. The transfer of HCs to high molecular weight (HMW) HA is a reversible event whereby TSG-6 can shuffle HCs from one HA molecule to another. Therefore, HMW HA can serve as both an HC acceptor and an HC donor. In the present study, we show that transfer of HCs to low molecular weight HA oligosaccharides is an irreversible event where subsequent shuffling does not occur, i.e. HA oligosaccharides from 8 to 21 monosaccharide units in length can serve as HC acceptors, but are unable to function as HC donors. We show that the HC-HA complex is present in the synovial fluid of mice subjected to systemic and monoarticular mouse models of rheumatoid arthritis. Furthermore, we demonstrate that HA oligosaccharides can be used, with TSG-6, to irreversibly shuffle HCs from pathological, HMW HC-HA to HA oligosaccharides, thereby restoring HC-HA matrices from the inflamed joint to their normal state, unmodified with HCs. This process was also effective for HC-HA in the synovial fluid of human rheumatoid arthritis patients (in vitro).

Pathological conditions involving extracellular hemoglobin: molecular mechanisms, clinical significance, and novel therapeutic opportunities for α(1)-microglobulin

Hemoglobin (Hb) is the major oxygen (O(2))-carrying system of the blood but has many potentially dangerous side effects due to oxidation and reduction reactions of the heme-bound iron and O(2). Extracellular Hb, resulting from hemolysis or exogenous infusion, is shown to be an important pathogenic factor in a growing number of diseases. This review briefly outlines the oxidative/reductive toxic reactions of Hb and its metabolites. It also describes physiological protection mechanisms that have evolved against extracellular Hb, with a focus on the most recently discovered: the heme- and radical-binding protein α(1)-microglobulin (A1M). This protein is found in all vertebrates, including man, and operates by rapidly clearing cytosols and extravascular fluids of heme groups and free radicals released from Hb. Five groups of pathological conditions with high concentrations of extracellular Hb are described: hemolytic anemias and transfusion reactions, the pregnancy complication pre-eclampsia, cerebral intraventricular hemorrhage of premature infants, chronic inflammatory leg ulcers, and infusion of Hb-based O(2) carriers as blood substitutes. Finally, possible treatments of these conditions are discussed, giving a special attention to the described protective effects of A1M.

Determination of urinary trypsin inhibitor provides insight into postoperative complications in patients following esophagectomy

The urinary trypsin inhibitor (UTI) is responsible for most of the antitryptic activity in urine and is excreted in increased amounts in urine under certain pathological conditions such as cancer and bacterial infections. Our aim in this study was to better understand the mechanisms responsible for the increase in UTI excretion on surgical stress and thus to better appreciate the information provided by inflammatory mediators. Thirty-one consecutive patients who underwent radical esophagectomy for esophageal cancer were investigated in this study. We determined serum UTI and polymorphonuclear cell elastase (PMNE), urine UTI and evaluated the effectiveness of preoperative administration of methylprednisolone on the postoperative clinical course and adverse inflammatory reactions. The results revealed that urine UTI and serum PMNE levels in the steroid group were significantly lower than those in the non-steroid group. In addition, UTI levels correlated positively with serum levels of aminotransferases. More importantly, the maximum level of urine UTI in patients without complications was lower than that in patients with complications. These results suggest that urine UTI provides useful information concerning postoperative clinical course, and that preoperative administration of methylprednisolone may contribute to decrease postoperative complications following esophagectomy.

Systemic differential gene regulation of the inter-α-trypsin inhibitor family in acute necrotizing pancreatitis in mice

BACKGROUND

Therapy for systemic complications in severe necrotizing pancreatitis remains symptomatic owing to the unavailability of more specific therapeutic targets. We investigated the differential gene expression in typically affected organs in a mouse model of severe necrotizing pancreatitis.

METHODS

Acute necrotizing pancreatitis was induced in mice by retrograde infusion of taurocholate into the common bile duct. Microarray hybridization was subsequently performed with mRNA isolated from the spleen, liver, intestine, and lungs. Additionally, quantitative real-time polymerase chain reaction was performed to confirm the microarray results.

RESULTS

Severe necrotizing pancreatitis induced widespread changes in gene expression, affecting 27.20% of the genes tested in the spleen and 29.07% in the liver. Fewer genes were differentially regulated in the intestine (10.28%) and the lungs (10.75%). Only 10 genes were found to be upregulated in all 4 organs using microarray analysis. This upregulation in all organs was confirmed by quantitative real-time polymerase chain reaction for only 3 molecules. These molecules were lipocalin 2, insulin-like growth factor binding protein 1, and CD14. Additionally we observed significantly aberrant gene regulation of inter-α-trypsin inhibitor family members in several organs.

CONCLUSIONS

Differential gene regulation in severe necrotizing pancreatitis is far more organ specific than anticipated, with only 3 molecules uniformly regulated systemically. The inter-α-trypsin inhibitor family of molecules appears to play a crucial biologic role in the systemic inflammatory response in acute pancreatitis. Finally, owing to its regulation and function, α1-microglobulin (or bikunin) may be a suitable predictive marker of the systemic inflammatory response syndrome in acute pancreatitis.

Inhibition of proteasomal proteolysis affects expression of extracellular matrix components and steroidogenesis in porcine oocyte-cumulus complexes

Porcine oocyte-cumulus complexes (OCCs) form an expanded cumulus extracellular matrix (ECM) in response to gonadotropins during meiotic maturation. Essential components of ECM are hyaluronan (HA), tumor necrosis factor α-induced protein 6 (TNFAIP6) and heavy chains (HC) of interalpha-trypsin inhibitor. To form expanded cumulus ECM, intermediate complexes (TNFAIP6-HC) must bind to HA to allow HC transfer onto HA. Protein turnover by the ubiquitin-proteasome pathway is poorly characterized in this process. It is known that the specific proteasomal inhibitor MG132 prevents cumulus expansion and formation of ECM. To determine whether inhibition of proteasomal proteolysis with MG132 affects cumulus cell steroidogenesis and expression of the cumulus expansion-related components (hyaluronan synthase type 2, HAS2, TNFAIP6) we cultured porcine OCCs and granulosa cells (GCs) in a medium supplemented with FSH/LH. Methods performed included real-time reverse transcription PCR, immunofluorescence and RIAs. The expression of TNFAIP6 and HAS2 transcripts increased significantly after the stimulation of OCCs and GCs with FSH/LH. In contrast, treatment with MG132 reduced the expression of TNFAIP6 and HAS2. Hyaluronan was detected with biotinylated HA-binding proteins within FSH/LH-stimulated expanded OCCs but not in those treated with MG132. Progesterone production, although increased almost three times after OCCs stimulation with FSH/LH, was significantly suppressed by MG132. The FSH/LH-stimulated a 40-fold increase in progesterone secretion by GCs was inhibited in the presence of MG132. In conclusion, MG132 affects progesterone secretion and expression of cumulus expansion-related components by cumulus and GCs, suggesting the requirement of ubiquitin-proteasome pathway-regulated protein turnover for formation of ECM during cumulus expansion in the preovulatory period in the pig.

Sequencing and gene expression of the porcine ITIH SSC13 cluster and its effect on litter size in an Iberian × Meishan F2 population

The aim of the present study was to identify polymorphisms and to analyze endometrial gene expression of the porcine SSC13 ITIH cluster that could explain differences in prolificacy of 255 F(2) sows derived from an Iberian (Ib)×Meishan (Me) intercross in which QTL for the number of piglets born alive (NBA) and total number of piglets born (TNB) were previously detected on this chromosome. Sequencing of ITIH-1, -3, and -4 mRNAs was done and several polymorphisms segregating within the Ib×Me population were found in all three genes. Significant associations with NBA were found for two SNPs from ITIH-1, four from ITIH-3, and four SNPs from ITIH-4 (p<0.05). Haplotypes for the significant SNPs were calculated by segregation analysis and a marker assisted association test indicated that the alleles coming from the Meishan breed had a favorable effect on NBA for all three genes. Interestingly, some of the significant SNPs were located within the von Willebrand domain of the ITIH proteins, the binding site of molecules essential for the synthesis of the extracellular matrix during cumulus expansion. Gene expression analyses also revealed differences in the expression level of the ITIH-3 gene regarding the prolificacy performance (high or low) and the uterus sample (apical or basal).

Biomarkers: the future

The future application of biomarkers in critical illness will be to select and guide therapy. Specific biomarkers could identify a pathophysiologic perturbation or noxious mediator to counteract or the need to replete a deficient protective protein. Functional genomics could identify patients at risk for illness or at risk for a poor outcome in critical illness. Genetic expression studies could help differentiate patients with sepsis from those with noninfectious inflammation and could also help to monitor illnesses over time. Expressional and functional proteomics could lead to the identification of new biomarkers and organ-specific therapies.

Implication of the oligomeric state of the N-terminal PTX3 domain in cumulus matrix assembly

Pentraxin 3 (PTX3) plays a key role in the formation of the hyaluronan-rich matrix of the cumulus oophorus surrounding ovulated eggs that is required for successful fertilization and female fertility. PTX3 is a multimeric protein consisting of eight identical protomers held together by a combination of non-covalent interactions and disulfide bonds. Recent findings suggest that the oligomeric status of PTX3 is important for stabilizing the cumulus matrix. Because the role of PTX3 in the cumulus resides in the unique N-terminal sequence of the protomer, we investigated further this issue by testing the ability of distinct Cys/Ser mutants of recombinant N-terminal region of PTX3 (N_{_}PTX3) with different oligomeric arrangement to promote in vitro normal expansion in cumuli from Ptx3-null mice. Here we report that the dimer of the N_{_}PTX3 is unable to rescue cumulus matrix organization, and that the tetrameric assembly of the protein is the minimal oligomeric state required for accomplishing this function. We have previously demonstrated that PTX3 binds to HCs of IαI and TSG-6, which are essential for cumulus matrix formation and able to interact with hyaluronan. Interestingly, here we show by solid-phase binding experiments that the dimer of the N_{_}PTX3 retains the ability to bind to both IαI and TSG-6, suggesting that the octameric structure of PTX3 provides multiple binding sites for each of these ligands. These findings support the hypothesis that PTX3 contributes to cumulus matrix organization by cross-linking HA polymers through interactions with multiple HCs of IαI and/or TSG-6. The N-terminal PTX3 tetrameric oligomerization was recently reported to be also required for recognition and inhibition of FGF2. Given that this growth factor has been detected in the mammalian preovulatory follicle, we wondered whether FGF2 negatively influences cumulus expansion and PTX3 may also serve in vivo to antagonize its activity. We found that a molar excess of FGF2, above PTX3 binding capacity, does not affect in vitro cumulus matrix formation thus ruling out this possibility. In conclusion, the data strength the view that PTX3 acts as a nodal molecule in cross-linking HA in the matrix.

Plasma proteome analysis in diet-induced obesity-prone and obesity-resistant rats

One of the major issues in the field of obesity is why some humans become obese and others resist development of obesity when exposed to high-calorie diets. Despite the same genetic background, namely obesity-prone (OP) and -resistant (OR) rats, differing responses have been demonstrated in a high fat diet-induced rodent model. The aim of the present study was to discover novel obesity-related biomarkers for susceptibility and/or resistance to obesity by proteomic analysis of OP and OR rat plasma. After feeding of high fat diet, OP rats gained approximately 25% more body weight than OR rats and were used for proteomic analysis using 2-DE combined with MALDI-TOF-MS. We categorized identified proteins into three groups by analysis of both average spot density in each group and individual spot density of six rats as a function of body weight. Consequently, category (1) included inter-α-inhibitor H4 heavy chain and fetuin B precursor, which can be used as novel plasma biomarkers for risk of obesity. Nine proteins of category (2) and (3) can also be plausible plasma markers in the study of obesity. This proteomic study is an important advancement over the previous steps needed for identification of OP and OR rats.

Inter-alpha inhibitor protein level in neonates predicts necrotizing enterocolitis

OBJECTIVES

To compare inter-alpha inhibitor protein (IaIp) levels in neonates with proven necrotizing enterocolitis (NEC) and neonates with other, nonspecific abdominal disorders.

STUDY DESIGN

This was a prospective observational study of neonates in the neonatal intensive care unit. NEC was diagnosed according to Bell's staging criteria. The nNeonates in the control group had a nonspecific abdominal disorder, but no radiographic evidence of NEC and no disease progression. All neonates with radiographically confirmed NEC were included. Plasma IaIp levels were quantitated by enzyme-linked immunosorbent assay.

RESULTS

Seventeen neonates had confirmed NEC, and 34 neonates had nonspecific abdominal disorders that improved rapidly. Gestational age, postnatal age, weight, sex, maternal obstetric variables, rupture of membranes, and mode of delivery did not differ between the two groups. Mean IaIp level was significantly lower in the NEC group compared with the control group (137 ± 38 mg/L; 95% confidence interval [CI], 118-157 mg/L vs 258 ± 53 mg/L; 95% CI, 238-277 mg/L; P <.0001).

CONCLUSIONS

The finding of significantly lower IaIp levels in neonates with NEC suggests that IaIp might be a useful, sensitive biomarker, allowing initiation of appropriate therapy and reducing antibiotic overuse in neonates with suspected but unproven NEC. Administration of IaIp may significantly reduce the severity of systemic inflammation and associated tissue injury.

Urinary trypsin inhibitor as a therapeutic option for endotoxin-related inflammatory disorders

IMPORTANCE OF THE FIELD

Urinary trypsin inhibitor (UTI), a serine protease inhibitor, has been widely used as a drug for patients with inflammatory disorders such as pancreatitis, shock and disseminated intravascular coagulation (DIC). Previous in vitro studies have demonstrated that serine protease inhibitors may have anti-inflammatory properties at sites of inflammation. However, the therapeutic effects of UTI in vivo remain unclarified, as commercial UTI has been developed to act against humans, with the activity and selectivity toward the relevant animal UTI being less characterized.

AREAS COVERED IN THIS REVIEW

In this review, we introduce the roles of UTI in experimental endotoxin (lipopolysaccharide; LPS)-related inflammatory disorders using UTI-deficient (-/-) and corresponding wild-type mice.

WHAT THE READER WILL GAIN

Our experiments using genetic approach suggest that endogenous UTI can protect against the systemic inflammatory response and subsequent organ injury induced by LPS, at least partly, through the inhibition of pro-inflammatory cytokine and chemokine expression, which provide important in vivo evidence and understanding about a protective role of UTI in inflammatory conditions.

TAKE HOME MESSAGE

Using genetically targeted mice selectively lacking UTI, UTI has been evidenced to provide an attractive 'rescue' therapeutic option for endotoxin-related inflammatory disorders such as DIC, acute lung injury and acute liver injury.

Bikunin and α1-microglobulin/bikunin precursor (AMBP) gene mutational screening in patients with kidney stones: a case-control study

OBJECTIVE

Bikunin is an inhibitor of kidney stone formation synthesized in the liver together with α(1)-microglobulin from the α(1)-microglobulin/bikunin precursor (AMBP) gene. The aim of this study was to investigate the possible association between bikunin/AMBP gene polymorphisms and urinary stone formation.

MATERIAL AND METHODS

To analyse the DNA, blood samples were taken from 75 kidney stone formers who had a familial stone history, 35 sporadic stone formers and 101 healthy individuals. Four exons of bikunin gene and five parts of the promoter region of the AMBP gene were screened using single-strand conformation polymorphism and nucleotide sequence analysis.

RESULTS

The Init-2 region of the promoter of AMBP gene had polymorphisms at positions -218 and -189 nt giving three different genotypes having 1,3, 2,4 and 1,2,3,4 alleles with frequencies of 17.06%, 60.19% and 22.75%, respectively, in all groups. Therefore, the Init-2 region appears to be polymorphic. As a result, the 1,3 allele has -218G and -189T complying with the reference database sequence, the 2,4 allele has -218G and T-189C substitution and the allele 1,2,3,4 genotype has substitutions at positions G-218C and T-189C.

CONCLUSIONS

There were no significant differences in allele distribution between patients and controls. These common alleles exist in the Turkish population independent of stone formation. These results are the first to demonstrate the existence of bikunin and AMBP promoter polymorphism. Although the Init-2 region of the AMBP gene is the binding site for various transcription factors, the results showed no association between these observed genotypes and stone-forming phenotypes.

Anti-inflammatory actions of serine protease inhibitors containing the Kunitz domain

INTRODUCTION

Protease inhibitors, including the Kunitz, Kazal, serpin and mucus families, play important roles in inhibiting protease activities during homeostasis, inflammation, tissue injury, and cancer progression. Interestingly, in addition to their anti-protease activity, protease inhibitors also often possess other intrinsic properties that contribute to termination of the inflammatory process, including modulation of cytokine expression, signal transduction and tissue remodeling. In this review we have tried to summarize recent findings on the Kunitz family of serine proteinase inhibitors and their implications in health and disease.

MATERIALS AND METHODS

A systematic search was performed in the electronic databases PubMed and ScienceDirect up to October 2009. We tried to limit the review to anti-inflammatory actions and actions not related to protease inhibition.

RESULTS AND CONCLUSION

Recent studies have demonstrated that the Kunitz inhibitors are not only protease inhibitors, but can also prevent inflammation and tissue injury and subsequently promote tissue remodeling.

Characterization of Renal Papillary Antigen 1 (RPA-1), a Biomarker of Renal Papillary Necrosis

Renal papillary necrosis (RPN) is a relatively common toxicity observed in preclinical drug safety testing. It is also observed in a variety of human diseases. RPN is difficult to diagnose without expensive scanning methods or histopathology. A noninvasive biomarker that could be detected at early stages of kidney damage would be of great value both to preclinical drug safety testing and in the clinic. An antibody raised to an unknown epitope of an antigen in rat kidney papilla was found to be specific for collecting duct cells in the kidney; this was termed renal papillary antigen 1 (RPA-1). In this study, the authors show that RPA-1 is an early biomarker of RPN in two different rat models of toxicity: 2-bromoethanamine (BEA) and N-phenylanthranilic acid (NPAA). RPA-1 can be detected in urine at early stages of toxicity and correlates well with the histopathology observed. We also characterized the biochemical properties of RPA-1 and found that the antigen is a high molecular weight membrane bound glycoprotein, with the epitope likely to be carried on an N-linked carbohydrate structure. This study demonstrates that RPA-1 is an excellent marker of RPN that can be used to detect this toxicity in preclinical safety testing.

Quali-quantitative analysis of urinary glycosaminoglycans for monitoring glomerular inflammatory activity

OBJECTIVE

A 2-year follow-up study was carried out in patients with IgA nephropathy (IgAN) in order to verify the possible use of quali-quantitative analysis of urinary glycosaminoglycans (GAGs) as a prognostic index of disease and for drug treatment monitoring.

MATERIAL AND METHODS

Ten patients with IgAN were evaluated at four time points: baseline, and 6, 9 and 24 months later. GAGs were isolated from 24-h urine using ion-exchange chromatography on diethylaminoethyl-Sephacel, and concentrations were expressed as milligrams of hexuronate per gram of creatinine. GAG composition was determined by cellulose acetate electrophoresis and expressed as relative percentages by means of densitometric scanning of Alcian Blue-stained strips.

RESULTS

The relative content of total low-sulphated chondroitin sulphate species decreased significantly during the study period compared to baseline, whereas the relative percentages of heparan sulphate and chondroitin sulphate increased significantly. Moreover, a significant correlation was noted between the relative contents of urinary GAGs, renal function and inflammation indexes.

CONCLUSIONS

It is likely that the excretion of various types of GAGs may be related to different glomerular pathophysiological conditions. Therefore, the determination of urinary GAG composition may represent a reliable indicator of disease activity.

Novel serum markers of fibrosis progression for the follow-up of hepatitis C virus-infected patients

Liver biopsy is considered the gold-standard method for the assessment of liver fibrosis during follow-up of hepatitis C virus-infected patients, but this invasive procedure is not devoid of complications. The aim of the present study was to identify novel non-invasive markers of fibrosis progression. By microarray analysis, we compared transcript levels in two extreme stages of fibrosis from 16 patients. Informative transcripts were validated by real-time PCR and used for the assessment of fibrosis in 23 additional patients. Sixteen transcripts were found to be dysregulated during the fibrogenesis process. Among them, some were of great interest because their corresponding proteins could be serologically measured. Thus, the protein levels of inter-alpha inhibitor H1, serpin peptidase inhibitor clade F member 2, and transthyretin were all significantly different according to the four Metavir stages of fibrosis. In conclusion, we report here that dysregulation, at both the transcriptional and protein levels, exists during the fibrogenesis process. Our description of three novel serum markers and their potential use as serological tests for the non-invasive diagnosis of liver fibrosis open new opportunities for better follow-up of hepatitis C virus-infected patients.

[Novel prognostic marker in invasive breast cancer. ITIH5 expression is abrogated by aberrant promoter methylation]

We have recently characterized ITIH5 as a new extracellular matrix protein that exhibits clear expression loss in a variety of human tumour entities, including breast cancer. The aim of the present study was to decipher the molecular cause of ITIH5 expression loss in breast cancer and to learn more about the possible role of this molecule in cancer diseases. ITIH5 protein expression was found to be strongly reduced in 42% of invasive breast carcinomas-interestingly, with significant association with poor patient outcome. ITIH5 promoter methylation was frequently detected in breast cell lines and in primary carcinomas (40%), and it was functionally correlated with loss of ITIH5 mRNA expression. Moreover, ITIH5 promoter methylation was also significantly associated with poor clinical patient outcome and also with the occurrence of lymph node and distant metastases. In conclusion, we propose that ITIH5 may represent a novel metastasis repressor in human breast cancer. Both ITIH5 protein expression and ITIH5 promoter methylation may serve as prognostic biomarkers, thereby helping improve clinical patient outcome.

The role of inter-alpha inhibitor proteins in the diagnosis of neonatal sepsis

We evaluated Inter-alpha inhibitor proteins (IaIp) as a diagnostic marker in neonatal sepsis. Samples were collected from 573 neonates who were examined for suspected sepsis. IaIp level was significantly lower in the septic group (121+/-71 mg/L) than in the non-septic group (322+/-91 mg/L). The optimal cutoff value with the receiver operating characteristic curve was <or= 177 mg/L (sensitivity, 89.5%; specificity, 99%; positive predictive value, 95%; negative predictive value, 98%) with area under the curve of 0.94. IaIp is a more reliable diagnostic marker for neonatal sepsis than other available tests.

Study of the human plasma proteome of rheumatoid arthritis

In this study, we report a combined proteomic and peptidomic analysis of human plasma from patients with rheumatoid arthritis (RA) and controls. We used molecular weight cut-off filters (MWCO: 10kDa) to enrich low-molecular-weight (LMW) peptides from human plasma. The peptide fraction was analyzed without trypsin digestion by capillary reversed-phase high-performance liquid chromatography (HPLC) coupled to a linear ion trap-FT-MS system, which identified 771 unique peptides in the peptidome study (from 145 protein progenitors). An anti-albumin/anti-IgG column was used to remove albumin and immunoglobulin G (IgG) from the human plasma. After that, the albumin/IgG-depleted sample was fractionated into a bound fraction and an unbound fraction on a multi-lectin affinity column (M-LAC). LC-MS analysis of the corresponding tryptic digests identified 308 proteins using the M-LAC approach. Relative differences in the following protein classifications were observed in the RA human plasma samples compared with controls: structural proteins, immuno-related proteins, protease inhibitors, coagulation proteins, transport proteins and apolipoproteins. While some of these proteins/peptides have been previously reported to be associated with RA disease such as calgranulin A, B, C and C-reactive protein, several others were newly identified (such as thymosin beta4, actin, tubulin, and vimentin), which may further the understanding of the disease pathogenesis. Moreover, we have found that the peptidomic and glycoproteomic approaches were complementary and allow a more complete picture of the human plasma proteome which can be valuable in studies of disease etiology.

Development and validation of an ELISA for the quantification of pig major acute phase protein (Pig-MAP)

Measurement of acute phase proteins (APPs) levels in blood is increasingly being used for monitoring health and welfare in farm animals. In this work a sandwich-type ELISA for the quantification of pig Major Acute phase Protein (Pig-MAP), one of the main APP in pigs, has been developed and validated. Two Pig-MAP specific monoclonal antibodies were developed in mouse. One of the monoclonal antibodies was fixed to microtiter plates and the other was coupled to horseradish peroxidase and used as detection antibody. To calibrate the assay dilutions of a standard pig serum of known Pig-MAP concentration were added to the plate in each assay. The assay showed good accuracy, kept linearity under dilution and recovery was proportional. The detection limit was 0.1 microg/mL. Precision was adequate with coefficients of variation lower than 8% for both inter and intra-assays. A good linear correlation between Pig-MAP concentration values obtained by ELISA and by radial immunodiffusion, used as reference method, was found (r = 0.978; beta = 1.02). Pig-MAP concentration was analysed in serum samples obtained from two pig herds of different health status (10 animals per age and herd, of 10, 12, 14, 18 weeks of age). Mean values obtained in the farm of low health status were higher than the obtained in the farm of high health status (p<0.001). In the farm of high health status, mean Pig-MAP concentration remained constant at the different ages analysed (mean values of 0.83+/-0.18 mg/mL) whereas in the farm of low health status differences between age groups were found. In this farm (low health status) mean values for the total of pigs analysed were of 1.68+/-0.74 mg/mL.

Hyaluronan and its binding proteins during cervical ripening and parturition: dynamic changes in size, distribution and temporal sequence

The uterine cervix undergoes changes during pregnancy and labor that transform it from a closed, rigid, collagen dense structure to one that is distensible, has a disorganized collagen matrix, and dilates sufficiently to allow birth. To protect the reproductive tract from exposure to the external environment, the cervix must be rapidly altered to a closed, undistensible structure after birth. Preparturition remodeling is characterized by increased synthesis of hyaluronan, decreased expression of collagen assembly genes and increased distribution of inflammatory cells into the cervical matrix. Postpartum remodeling is characterized by decreased hyaluronan (HA) content, increased expression of genes involved in assembly of mature collagen and inflammation. The focus of this study is to advance our understanding of functions HA plays in this dynamic process through characterization of HA size, structure and binding proteins in the mouse cervix. Changes in size and structure of HA before and after birth were observed as well as cell specific expression of HA binding proteins. CD44 expression is localized to the pericellular matrix surrounding the basal epithelia and on immune cells while inter alpha trypsin inhibitor (IalphaI) and versican are localized to the stromal matrix. Colocalization of HA and IalphaI is most pronounced after birth. Upregulation of the versican degrading protease, ADAMTS1 occurs in the cervix prior to birth. These studies suggest that HA has multiple, cell specific functions in the cervix that may include modulation of tissue structure and integrity, epithelial cell migration and differentiation, and inflammatory responses.

Frequent expression loss of Inter-alpha-trypsin inhibitor heavy chain (ITIH) genes in multiple human solid tumors: a systematic expression analysis

Background

The inter-alpha-trypsin inhibitors (ITI) are a family of plasma protease inhibitors, assembled from a light chain – bikunin, encoded by AMBP – and five homologous heavy chains (encoded by ITIH1, ITIH2, ITIH3, ITIH4, and ITIH5), contributing to extracellular matrix stability by covalent linkage to hyaluronan. So far, ITIH molecules have been shown to play a particularly important role in inflammation and carcinogenesis.

Methods

We systematically investigated differential gene expression of the ITIH gene family, as well as AMBP and the interacting partner TNFAIP6 in 13 different human tumor entities (of breast, endometrium, ovary, cervix, stomach, small intestine, colon, rectum, lung, thyroid, prostate, kidney, and pancreas) using cDNA dot blot analysis (Cancer Profiling Array, CPA), semiquantitative RT-PCR and immunohistochemistry.

Results

We found that ITIH genes are clearly downregulated in multiple human solid tumors, including breast, colon and lung cancer. Thus, ITIH genes may represent a family of putative tumor suppressor genes that should be analyzed in greater detail in the future. For an initial detailed analysis we chose ITIH2 expression in human breast cancer. Loss of ITIH2 expression in 70% of cases (n = 50, CPA) could be confirmed by real-time PCR in an additional set of breast cancers (n = 36). Next we studied ITIH2 expression on the protein level by analyzing a comprehensive tissue micro array including 185 invasive breast cancer specimens. We found a strong correlation (p < 0.001) between ITIH2 expression and estrogen receptor (ER) expression indicating that ER may be involved in the regulation of this ECM molecule.

Conclusion

Altogether, this is the first systematic analysis on the differential expression of ITIH genes in human cancer, showing frequent downregulation that may be associated with initiation and/or progression of these malignancies.

Equivalent involvement of inter-alpha-trypsin inhibitor heavy chain isoforms in forming covalent complexes with hyaluronan

Inter-alpha-trypsin inhibitor (IalphaI) family molecules are composed of a common light chain of chondroitin sulfate proteoglycan, bikunin, and one or two of three genetically distinct heavy chain isoforms (designated HC1, 2, 3) that are bound covalently to the chondroitin sulfate chain. Hyaluronan can substitute for chondroitin sulfate to form a covalent complex with HCs. Important physiological and pathological roles of the formation of HC-hyaluronan complex have been well established. However, the involvement of the three HC isoforms in the assembly of IalphaI family molecules and the subsequent formation of SHAP-hyaluronan complex has not been studied yet in mice. In this study, we showed that mouse IalphaI and pre-alpha inhibitor contain HC1 approximately HC3 and HC3, respectively. All three HC isoforms are found in the SHAP-hyaluronan complexes of physiological or pathological origins as well as that formed in vitro, indicating that the three HC isoforms are all potential in forming complex with hyaluronan.

Structure and function of inter-alpha-trypsin inhibitor heavy chains

Inter-alpha-trypsin inhibitor family proteins are mainly detected in plasma and urine and comprise the common light chain bikunin and at least 6 closely related heavy chains. The bikunin moiety exhibits protease inhibitory activity and has been studied extensively; however, the heavy chains have been largely overlooked. Recent studies clearly indicate that the heavy chain moieties have important biological functions either in association with or independent of bikunin. Because the heavy chains comprise the main part of the protein structure of this family, it is important to understand their functions. This review summarizes the domain structural features of heavy chains, the heavy chain-interacting molecules identified thus far, and the association of heavy chains with diseases to encourage the discovery of novel heavy chains-interacting molecules and to gain a deeper insight into their functions.

Expression of the hepatic specific V1 messenger ribonucleic acid of the human growth hormone receptor gene is regulated by hepatic nuclear factor (HNF)-4alpha2 and HNF-4alpha8

Human (h) GH plays an essential role in growth and metabolism, and its effectiveness is modulated by the availability of its specific receptor [hGH receptor (hGHR)] on target cells. The hGHR gene has a complex 5'-regulatory region containing multiple first exons. Seven are clustered within two small regions: V2,V3,V9 (module A) and V1,V4,V7,V8 (module B). Module A-derived mRNAs are ubiquitously expressed whereas those from module B are only found in postnatal liver, suggesting developmental- and liver-specific regulation of module B hGHR gene expression. To characterize the elements regulating module B activity, we studied a 1.8-kb promoter of the highest expressing exon in liver, V1. This promoter was repressed in transfection assays; however, either 5'- or 3'-deletions relieved this, suggesting the presence of multiple negative regulatory elements. Six putative hepatic nuclear factor 4 (HNF-4) response elements were identified. We determined that HNF-4alpha is developmentally regulated in the human liver: HNF-4alpha2 and HNF-4alpha8 are expressed in fetal hepatocytes but only HNF-4alpha2 is expressed in postnatal liver. Transient transfection assays demonstrated that HNF-4alpha2 and HNF-4alpha8 have a similar dual effect on V1 transcription: activation via site 1 in the proximal promoter and repression through site 6, approximately 1.7 kb upstream. EMSA/electrophoretic mobility supershift assays and chromatin immunoprecipitation analyses confirmed these two sites are bound by HNF-4alpha. Based on these data, we speculate there are multiple regions working together to repress the expression of V1 hGHR transcripts in tissues other than the normal postnatal liver, and that HNF-4alpha is a good candidate for regulating V1 hGHR expression in the human hepatocyte.

Potential opportunity in the development of new therapeutic agents based on endogenous and exogenous inhibitors of the proprotein convertases

The proprotein convertases (PCs) are responsible for the endoproteolytic processing of various protein precursors (e.g., growth factors, receptors, adhesion molecules, and matrix metalloproteinases) implicated in several diseases such as obesity, diabetes, atherosclerosis, cancer, and Alzheimer disease. The potential clinical and pharmacological role of the PCs has fostered the development of various PC‐inhibitors. In this review we summarized the recent findings on PCs inhibitors, their mode of actions and potential use in the therapy of various diseases. © 2006 Wiley Periodicals, Inc. Med Res Rev, 27, No. 5, 631–648, 2007

Renal inter-alpha-trypsin inhibitor heavy chain 3 increases in calcium oxalate stone-forming patients

Inter-alpha-trypsin inhibitor heavy-chain proteins bind to the protease inhibitor bikunin and to hyaluronan, stabilizes extracellular matrix in various tissues, and also inhibits calcium oxalate crystallization in vitro. In both normal and stone-forming patients, we found heavy chain 3 and hyaluronan in the interstitial matrix of the kidney. Osteopontin was found in the collecting duct, thin loop of Henle, and urothelial cells. In stone formers, heavy chain 3 was also present in collecting duct, thin loop, and interstitial cells. Heavy chain 3 and osteopontin colocalized in plaque matrix and urothelial cells. Within individual plaque spherules, heavy chain 3 was found in the matrix layer while osteopontin was located along the crystal-matrix interface. Bikunin was present only in the collecting duct apical membranes and the loop cell cytoplasm of stone formers colocalizing with osteopontin and heavy chain 3. Widespread heavy chain 3 was only present in stone formers, whereas osteopontin was similarly expressed in normal and stone-forming subjects except for its localization in plaques of the stone formers. This is consistent with studies linking inter-alpha-trypsin inhibitor components to human stone disease, although their role is still unclear. Heavy chain 3 may also play a role in stabilizing hyaluronan in the renal interstitial matrix.

How does amniotic membrane work?

Transplantation of amniotic membrane as a temporary or permanent graft promotes epithelial wound healing and exerts potent anti-inflammatory and anti-scarring effects on the ocular surface. These actions depend on the killing of allogeneic amniotic cells and preservation of the cytokine-containing matrix during the preparation of the amniotic membrane. This review describes how these actions inherently operate in utero and how amniotic membrane transplantation aims to recreate such a fetal environment to exert these actions by insulating the surgical site from the host environment. These actions also render the amniotic membrane a unique niche capable of expanding both epithelial and mesenchymal progenitor cells ex vivo, while maintaining their normal cell phenotypes. As a result, the amniotic membrane becomes an ideal substrate for engineering different types of ocular surface tissues for transplantation. Further studies investigating the exact molecular mechanism by which the amniotic membrane works will undoubtedly unravel additional applications in reconstruction and engineering of both ocular and nonocular tissues in the burgeoning field of regenerative medicine.

PTX3 interacts with inter-alpha-trypsin inhibitor: implications for hyaluronan organization and cumulus oophorus expansion

Pentraxin 3 (PTX3) and heavy chains (HCs) of inter-alpha-trypsin inhibitor (IalphaI) are essential for hyaluronan (HA) organization within the extracellular matrix of the cumulus oophorus, which is critical for in vivo oocyte fertilization and female fertility. In this study, we examined the possibility that these molecules interact and cooperate in this function. We show that HCs and PTX3 colocalize in the cumulus matrix and coimmunoprecipitate from cumulus matrix extracts. Coimmunoprecipitation experiments and solid-phase binding assays performed with purified human IalphaI and recombinant PTX3 demonstrate that their interaction is direct and not mediated by other matrix components. PTX3 does not bind to IalphaI subcomponent bikunin and, accordingly, bikunin does not compete for the binding of PTX3 to IalphaI, indicating that PTX3 interacts with IalphaI subcomponent HC only. Recombinant PTX3-specific N-terminal region, but not the PTX3-pentraxin C-terminal domain, showed the same ability as full-length protein to bind to HCs and to enable HA organization and matrix formation by Ptx3(-/-) cumulus cell oocyte complexes cultured in vitro. Furthermore, a monoclonal antibody raised against PTX3 N terminus, which inhibits PTX3/IalphaI interaction, also prevents recombinant full-length PTX3 from restoring a normal phenotype to in vitro-cultured Ptx3(-/-) cumuli. These results indicate that PTX3 directly interacts with HCs of IalphaI and that such interaction is essential for organizing HA in the viscoelastic matrix of cumulus oophorus, highlighting a direct functional link between the two molecules.