Proteins of the inter-alpha-trypsin inhibitor family stabilize the cumulus extracellular matrix through their direct binding with hyaluronic acid

ITIH5 as a multifaceted player in pancreatic cancer suppression, impairing tyrosine kinase signaling, cell adhesion and migration

Inter-alpha-trypsin inhibitor heavy chain 5 (ITIH5) has been identified as a metastasis suppressor gene in pancreatic cancer. Here, we analyzed ITIH5 promoter methylation and protein expression in The Cancer Genome Atlas (TCGA) dataset and three tissue microarray cohorts (n = 618), respectively. Cellular effects, including cell migration, focal adhesion formation and protein tyrosine kinase activity, induced by forced ITIH5 expression in pancreatic cancer cell lines were studied in stable transfectants. ITIH5 promoter hypermethylation was associated with unfavorable prognosis, while immunohistochemistry demonstrated loss of ITIH5 in the metastatic setting and worsened overall survival. Gain-of-function models showed a significant reduction in migration capacity, but no alteration in proliferation. Focal adhesions in cells re-expressing ITIH5 exhibited a smaller and more rounded phenotype, typical for slow-moving cells. An impressive increase of acetylated alpha-tubulin was observed in ITIH5-positive cells, indicating more stable microtubules. In addition, we found significantly decreased activities of kinases related to focal adhesion. Our results indicate that loss of ITIH5 in pancreatic cancer profoundly affects its molecular profile: ITIH5 potentially interferes with a variety of oncogenic signaling pathways, including the PI3K/AKT pathway. This may lead to altered cell migration and focal adhesion formation. These cellular alterations may contribute to the metastasis-inhibiting properties of ITIH5 in pancreatic cancer.

Hepatokine ITIH3 protects against hepatic steatosis by downregulating mitochondrial bioenergetics and de novo lipogenesis

Recent studies demonstrate that liver secretory proteins, also known as hepatokines, regulate normal development, obesity, and simple steatosis to non-alcoholic steatohepatitis (NASH) progression. Using a panel of ∼100 diverse inbred strains of mice and a cohort of bariatric surgery patients, we found that one such hepatokine, inter-trypsin inhibitor heavy chain 3 (ITIH3), was progressively lower in severe non-alcoholic fatty liver disease (NAFLD) disease states highlighting an inverse relationship between Itih3/ITIH3 expression and NAFLD severity. Follow-up animal and cell culture models demonstrated that hepatic ITIH3 overexpression lowered liver triglyceride and lipid droplet accumulation, respectively. Conversely, ITIH3 knockdown in mice increased the liver triglyceride in two independent NAFLD models. Mechanistically, ITIH3 reduced mitochondrial respiration and this, in turn, reduced liver triglycerides, via downregulated de novo lipogenesis. This was accompanied by increased STAT1 signaling and Stat3 expression, both of which are known to protect against NAFLD/NASH. Our findings indicate hepatokine ITIH3 as a potential biomarker and/or treatment for NAFLD.

A Proteomic Analysis of Human Follicular Fluid: Proteomic Profile Associated with Embryo Quality

Embryo selection is a key point of in vitro fertilization (IVF). The most commonly used method for embryo selection is morphological assessment. However, it is sometimes inaccurate. Follicular fluid (FF) contains a complex mixture of proteins that are essential for follicle development and oocyte maturation. Analyzing human FF proteomic profiles and identifying predictive biomarkers might be helpful for evaluating embryo quality. A total of 22 human FF samples were collected from 19 infertile women who underwent IVF/intracytoplasmic sperm injection (ICSI) treatment between October 2021 and November 2021. FFs were grouped into two categories on the basis of the day 3 embryo quality, grade I or II in the hqFF group and grade III in the nhqFF group. FF was analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS). The key differentially expressed proteins (DEPs) were validated by parallel reaction monitoring (PRM) and enzyme-linked immunosorbent assay (ELISA). Differentially expressed proteins were further analyzed using DAVID software. A total of 558 proteins were identified, of which 50 proteins were differentially expressed in the hqFF versus nhqFF group, including 32 upregulated proteins (> 1.20-fold, P < 0.05) and 18 downregulated proteins (< 0.67-fold, P < 0.05). Bioinformatics analyses showed that the upregulated DEPs were enriched in components of the coagulation and complement systems and negative regulation of peptidase activity, while the downregulated DEPs were enriched in molecular function of extracellular matrix structural and constituent collagen binding. Our results suggested that a number of protein biomarkers in FF were associated with embryo quality. It may help develop an effective and noninvasive method for embryo selection.

Hyaluronic acid synthesis, degradation, and crosslinking in equine osteoarthritis: TNF-α-TSG-6-mediated HC-HA formation

BACKGROUND

TNF-α-stimulated gene 6 (TSG-6) protein, a TNF-α-responsive hyaladherin, possesses enzymatic activity that can catalyze covalent crosslinks of the polysaccharide hyaluronic acid (HA) to another protein to form heavy chain-hyaluronic acid (HC-HA) complexes in pathological conditions such as osteoarthritis (OA). Here, we examined HA synthase and inflammatory gene expression; synovial fluid HA, TNF-α, and viscosity; and TSG-6-mediated HC-HA complex formation in an equine OA model. The objectives of this study were to (1) evaluate the TNF-α-TSG-6-HC-HA signaling pathway across multiple joint tissues, including synovial membrane, cartilage, and synovial fluid, and (2) determine the impact of OA on synovial fluid composition and biophysical properties.

METHODS

HA and inflammatory cytokine concentrations (TNF-α, IL-1β, CCL2, 3, 5, and 11) were analyzed in synovial fluid from 63 OA and 25 control joints, and HA synthase (HAS1-3), TSG-6, and hyaluronan-degrading enzyme (HYAL2, HEXA) gene expression was measured in synovial membrane and cartilage. HA molecular weight (MW) distributions were determined using agarose gel electrophoresis and solid-state nanopore measurements, and HC-HA complex formation was detected via immunoblotting and immunofluorescence. SEC-MALS was used to evaluate TSG-6-mediated HA crosslinking, and synovial fluid and HA solution viscosities were analyzed using multiple particle-tracking microrheology and microfluidic measurements, respectively.

RESULTS

TNF-α concentrations were greater in OA synovial fluid, and TSG6 expression was upregulated in OA synovial membrane and cartilage. TSG-6-mediated HC-HA complex formation was greater in OA synovial fluid and tissues than controls, and HC-HA was localized to both synovial membrane and superficial zone chondrocytes in OA joints. SEC-MALS demonstrated macromolecular aggregation of low MW HA in the presence of TSG-6 and inter-α-inhibitor with concurrent increases in viscosity.

CONCLUSIONS

Synovial fluid TNF-α concentrations, synovial membrane and cartilage TSG6 gene expression, and HC-HA complex formation were increased in equine OA. Despite the ability of TSG-6 to induce macromolecular aggregation of low MW HA with resultant increases in the viscosity of low MW HA solutions in vitro, HA concentration was the primary determinant of synovial fluid viscosity rather than HA MW or HC-HA crosslinking. The TNF-α-TSG-6-HC-HA pathway may represent a potential therapeutic target in OA.

A clinical model including protein biomarkers predicts radiographic knee osteoarthritis: a prospective study using data from the Osteoarthritis Initiative

OBJECTIVE

We aimed to provide a model to predict the prospective development of radiographic KOA (rKOA).

METHOD

Baseline sera from 333 non-radiographic KOA subjects belonging to OA Initiative (OAI) who developed or not, rKOA during a follow-up period of 96 months were used in this study. The exploratory cohort included 200 subjects, whereas the replication cohort included 133. The levels of inter-alpha trypsin inhibitor heavy chain 1 (ITIH1), complement C3 (C3) and calcyclin (S100A6), identified in previous large proteomic analysis, were analyzed by using sandwich immunoassays on suspension bead arrays. The association of protein levels and clinical covariates with rKOA incidence was assessed by combining logistic regression analysis, Receiver Operating Characteristic (ROC) analysis, Integrated Discrimination Improvement (IDI) analysis and Kaplan-Meier curves.

RESULTS

Levels of ITIH1, C3 and S100A6 were significantly associated with the prospective development of rKOA, showing an area under the curve (AUC) of 0.713 (0.624-0.802), 0.708 (0.618-0.799) and 0.654 (0.559-0.749), respectively to predict rKOA in the replication cohort. The inclusion of ITIH1 in the clinical model (age, gender, BMI, previous knee injury and WOMAC pain) improved the predictive capacity of the clinical covariates (AUC = 0.754 [0.670-0.838]) producing the model with the highest AUC (0.786 [0.705-0.867]) and the highest IDI index (9%). High levels of ITIH1 were also associated with an earlier onset of the disease.

CONCLUSION

A clinical model including protein biomarkers that predicts incident rKOA has been developed. Among the tested biomarkers, ITIH1 showed potential to improve the capacity to predict rKOA incidence in clinical practice.

Evolutionary, proteomic, and experimental investigations suggest the extracellular matrix of cumulus cells mediates fertilization outcomes

Studies of fertilization biology often focus on sperm and egg interactions. However, before gametes interact, mammalian sperm must pass through the cumulus layer; in mice, this consists of several thousand cells tightly glued together with hyaluronic acid and other proteins. To better understand the role of cumulus cells and their surrounding matrix, we perform proteomic experiments on cumulus oophorus complexes (COCs) in house mice (Mus musculus), producing over 24,000 mass spectra to identify 711 proteins. Seven proteins known to stabilize hyaluronic acid and the extracellular matrix were especially abundant (using spectral counts as an indirect proxy for abundance). Through comparative evolutionary analyses, we show that three of these evolve rapidly, a classic signature of genes that influence fertilization rate. Some of the selected sites overlap regions of the protein known to impact function. In a follow-up experiment, we compared COCs from females raised in two different social environments. Female mice raised in the presence of multiple males produced COCs that were smaller and more resistant to sperm-derived hyaluronidase compared to females raised in the presence of a single male, consistent with a previous study that demonstrated such females produced COCs that were more resistant to fertilization. Although cumulus cells are often thought of as enhancers of fertilization, our evolutionary, proteomic, and experimental investigations implicate their extracellular matrix as a potential mediator of fertilization outcomes.

In Sickness and in Health: The Immunological Roles of the Lymphatic System

The lymphatic system plays crucial roles in immunity far beyond those of simply providing conduits for leukocytes and antigens in lymph fluid. Endothelial cells within this vasculature are distinct and highly specialized to perform roles based upon their location. Afferent lymphatic capillaries have unique intercellular junctions for efficient uptake of fluid and macromolecules, while expressing chemotactic and adhesion molecules that permit selective trafficking of specific immune cell subsets. Moreover, in response to events within peripheral tissue such as inflammation or infection, soluble factors from lymphatic endothelial cells exert “remote control” to modulate leukocyte migration across high endothelial venules from the blood to lymph nodes draining the tissue. These immune hubs are highly organized and perfectly arrayed to survey antigens from peripheral tissue while optimizing encounters between antigen-presenting cells and cognate lymphocytes. Furthermore, subsets of lymphatic endothelial cells exhibit differences in gene expression relating to specific functions and locality within the lymph node, facilitating both innate and acquired immune responses through antigen presentation, lymph node remodeling and regulation of leukocyte entry and exit. This review details the immune cell subsets in afferent and efferent lymph, and explores the mechanisms by which endothelial cells of the lymphatic system regulate such trafficking, for immune surveillance and tolerance during steady-state conditions, and in response to infection, acute and chronic inflammation, and subsequent resolution.

Pan-cancer analysis identifies ITIH1 as a novel prognostic indicator for hepatocellular carcinoma

Although a previous pan-cancer study has reported the expression patterns of ITIHs in various tumors, their analyses have been restricted to limited cancer types. We thus comprehensively analyzed the expression profiles and clinical significances of ITIHs in a broader spectrum of cancers from TCGA. Our results showed that ITIHs were primarily down-regulated in tested cancers. The ITIH members were associated with either survival advantage or disadvantage, depending on the cancer type tested and the genes queried. Importantly, we for the first time demonstrated that ITIH1 had substantially decreased expression in liver hepatocellular carcinoma (LIHC) compared with corresponding normal tissue, and its down-regulation adversely impacted patient outcome. Moreover, ITIH1 expression was consistently declining during the progression of LIHC. Further analysis revealed that ITIH1 may be involved in cellular metabolic processes. Our findings established ITIH1 as a potential diagnostic and prognostic biomarker for LIHC, which awaits future experimental validation.

Hypoxia-inducible factor (HIF1alpha) inhibition modulates cumulus cell function and affects bovine oocyte maturation in vitro†

Various metabolic and hormonal factors expressed in cumulus cells are positively correlated with the in vitro maturation (IVM) of oocytes. However, the role of hypoxia sensing both during maturation of cumulus–oocyte complexes (COCs) as well as during the resumption of meiosis remains uncertain. HIF1alpha plays major roles in cellular responses to hypoxia, and here we investigated its role during bovine COC maturation by assessing the expression of related genes in cumulus cells. COCs were divided into the following groups: immature (control), in vitro matured (IVM/control), or matured in the presence of a blocker of HIF1alpha activity (echinomycin, IVM/E). We found an inhibition of cumulus cell expansion in IVM/E, compared with the IVM/control. Transcript levels of several factors (n = 13) were assessed in cumulus cells. Decreased expression of HAS2, TNFAIP6, TMSB4, TMSB10, GATM, GLUT1, CX43, COX2, PTGES, and STAR was found in IVM/E (P < 0.05). Additionally, decreased protein levels were detected for STAR, HAS2, and PCNA (P < 0.05), while activated-Caspase 3 remained unaffected in IVM/E. Progesterone output decreased in IVM/E. The application of PX-478, another blocker of HIF1alpha expression, yielded identical results. Negative effects of HIF1alpha suppression were further observed in the significantly decreased oocyte maturation and blastocyst rates from COCs matured with echinomycin (P < 0.05) or PX-478 (P < 0.05). These results support the importance of HIF1alpha for COC maturation and subsequent embryo development. HIF1alpha is a multidirectional factor controlling intercellular communication within COCs, steroidogenic activity, and oocyte development rates, and exerting effects on blastocyst rates.

Comparative Analysis of Porcine Follicular Fluid Proteomes of Small and Large Ovarian Follicles

Ovarian follicular fluid is widely used for in vitro oocyte maturation, but its in-depth characterization to extract full beneficial effects remains unclear. Here, we performed both shotgun (nanoscale liquid chromatography coupled to tandem mass spectrometry or nanoLC-MS/MS) and gel-based (two dimension-differential in-gel electrophoresis or 2D-DIGE) proteomics, followed by functional bioinformatics to compare the proteomes of follicular fluids collected from small (<4 mm) and large (>6-12 mm) follicles of pig ovaries. A total of 2321 unique spots were detected with the 2D-DIGE across small and large follicles, while 2876 proteins with 88% successful annotations were detected with the shotgun approach. The shotgun and 2D-DIGE approaches revealed about 426 and 300 proteins that were respectively common across samples. Six proteins detected with both technical approaches were significantly differently expressed between small and large follicles. Pathways such as estrogen and PI3K-Akt signaling were significantly enriched in small follicles while the complement and coagulation cascades pathways were significantly represented in large follicles. Up-regulated proteins in small follicles were in favor of oocyte maturation, while those in large follicles were involved in the ovulatory process preparation. Few proteins with potential roles during sperm-oocyte interactions were especially detected in FF of large follicles and supporting the potential role of the ovarian FF on the intrafallopian sperm migration and interaction with the oocyte.

A Single-Cell Transcriptional Roadmap of the Mouse and Human Lymph Node Lymphatic Vasculature

Single-cell transcriptomics promise to revolutionize our understanding of the vasculature. Emerging computational methods applied to high-dimensional single-cell data allow integration of results between samples and species and illuminate the diversity and underlying developmental and architectural organization of cell populations. Here, we illustrate these methods in the analysis of mouse lymph node (LN) lymphatic endothelial cells (LEC) at single-cell resolution. Clustering identifies five well-delineated subsets, including two medullary sinus subsets not previously recognized as distinct. Nearest neighbor alignments in trajectory space position the major subsets in a sequence that recapitulates the known features and suggests novel features of LN lymphatic organization, providing a transcriptional map of the lymphatic endothelial niches and of the transitions between them. Differences in gene expression reveal specialized programs for (1) subcapsular ceiling endothelial interactions with the capsule connective tissue and cells; (2) subcapsular floor regulation of lymph borne cell entry into the LN parenchyma and antigen presentation; and (3) pathogen interactions and (4) LN remodeling in distinct medullary subsets. LEC of the subcapsular sinus floor and medulla, which represent major sites of cell entry and exit from the LN parenchyma respectively, respond robustly to oxazolone inflammation challenge with enriched signaling pathways that converge on both innate and adaptive immune responses. Integration of mouse and human single-cell profiles reveals a conserved cross-species pattern of lymphatic vascular niches and gene expression, as well as specialized human subsets and genes unique to each species. The examples provided demonstrate the power of single-cell analysis in elucidating endothelial cell heterogeneity, vascular organization, and endothelial cell responses. We discuss the findings from the perspective of LEC functions in relation to niche formations in the unique stromal and highly immunological environment of the LN.

Proteomic analysis of follicular fluid during human ovulation

INTRODUCTION

Human ovulation is a biologically complex process that involves several biochemical factors, promoting follicular rupture and release of a fertilizable oocyte. Proteins which are present in follicular fluid at high concentrations during ovulation are likely to be active participants in the biochemical pathways of ovulation. The aim of the study was to identify, by use of a modern proteomic technique, proteins of human follicular fluid which are differentially regulated during ovulation of the natural menstrual cycle.

MATERIAL AND METHODS

This prospective experimental study over 3 years included women planned for laparoscopic sterilization. During surgery, retrieval of the dominant follicle was performed either at the preovulatory stage or during ovulation. Four women of preovulatory phase and four women of ovulatory phase met the predetermined criteria of hormone levels for respective phases, and samples of these were finally included out of the 15 women operated. Follicular fluid was aspirated from the excised follicle and subjected to mass spectrometry with the isobaric tags for relative and absolute quantification (iTRAQ) technology for isobaric tagging of peptides. This enables simultaneous identification and quantification of proteins. The protein profiles of the follicular fluid of the preovulatory phase and the ovulatory phase were analyzed, and proteins that were present were identified.

RESULTS

A total of 502 proteins were identified, several of which previously have not been identified in human follicular fluid. Of the 115 proteins that were found in all samples, 20 proteins were at higher levels during ovulation. These were inflammatory-related proteins, coagulation factors, proteins in lipid metabolism, complement factors and antioxidants. Five proteins were present in lower levels during ovulation, with three being enzymes and the other two proteins of lipid metabolism and iron transport.

CONCLUSIONS

Twenty-five follicular fluid proteins, with differential regulation during ovulation, were identified in human follicular fluid of the natural menstrual cycle. These proteins may have essential roles in the ovulatory cascade.

Amphiphilic dendrimers control protein binding and corona formation on liposome nanocarriers

Amphiphilic polyphenylene dendrimers adsorbed to liposomes alter the protein corona dependent on their charge and hydrophobicity.

Plasma Inter-Alpha-Trypsin Inhibitor Heavy Chains H3 and H4 Serve as Novel Diagnostic Biomarkers in Human Colorectal Cancer

Objective

Inter-alpha-trypsin inhibitor heavy chain H3 (ITIH₃) and inter-alpha-trypsin inhibitor heavy chain H4 (ITIH₄) are heavy chains of protein members belonging to the ITI family, which was associated with inflammation and carcinogenesis. However, the diagnostic value of ITIH₃ and ITIH₄ in human colorectal cancer (CRC) remains unknown.

Methods

In total, 101 CRC patients and 156 healthy controls were enrolled. The concentrations of ITIH₃ and ITIH₄ proteins in plasma samples of participants were assessed using enzyme-linked immunosorbent assay. ITIH₃ and ITIH₄ expressions in human CRC tissues were additionally assessed via immunohistochemical staining (IHC). Receiver operating characteristic (ROC) was applied to estimate the diagnostic power of the two proteins, and the net reclassification improvement (NRI) was adopted to evaluate the incremental predictive ability of ITIH₃/ITIH₄ when added to the tissue inhibitor of metalloproteinase-1 (TIMP-1).

Results

The plasma concentration of ITIH₃ in CRC patients (median: 4.370 μg/mL; range: 2.152–8.170 μg/mL) was significantly lower than that in healthy subjects (median: 4.715 μg/mL; range: 2.665–10.257 μg/mL; p < 0.001), while the ITIH₄ plasma level in subjects with CRC (median: 0.211 μg/mL; range: 0.099–0.592 μg/mL) was markedly increased relative to that in the control group (median: 0.134 μg/mL; range: 0.094–0.460 μg/mL, p < 0.001). Consistently, IHC score assessment showed a dramatic reduction in ITIH₃ expression and, conversely, upregulation of ITIH₄ in colorectal carcinoma specimens relative to adjacent normal colorectal tissues (p < 0.001 in both cases). The area under the curve (AUC) of the ROC for ITIH₄ (AUC = 0.801, 95% CI: 0.745–0.857) was higher than that for ITIH₃ (AUC = 0.638, 95% CI: 0.571–0.704, both p values < 0.001). The AUC of the ROC for combined ITIH₃ and ITIH₄ was even higher than that for carcinoembryonic antigen. NRI results showed that combining ITIH₃ and ITIH₄ with TIMP-1 significantly improved diagnostic accuracy (NRI = 17.12%, p = 0.002) for CRC patients compared to TIMP-1 alone.

Conclusions

Circulating ITIH₃ and ITIH₄ levels are associated with carcinogenesis in CRC, supporting their potential diagnostic utility as surrogate biomarkers for colorectal cancer detection.

The Impact of TCR Signal Strength on Resident Memory T Cell Formation during Influenza Virus Infection

Resident memory T cells (T_RM) in the lung are vital for heterologous protection against influenza A virus (IAV). Environmental factors are necessary to establish lung T_RM; however, the role of T cell-intrinsic factors like TCR signal strength have not been elucidated. In this study, we investigated the impact of TCR signal strength on the generation and maintenance of lung T_RM after IAV infection. We inserted high- and low-affinity OT-I epitopes into IAV and infected mice after transfer of OT-I T cells. We uncovered a bias in T_RM formation in the lung elicited by lower affinity TCR stimulation. TCR affinity did not impact the overall phenotype or long-term maintenance of lung T_RM Overall, these findings demonstrate that T_RM formation is negatively correlated with increased TCR signal strength. Lower affinity cells may have an advantage in forming T_RM to ensure diversity in the Ag-specific repertoire in tissues.

Molecular organization and mechanical properties of the hyaluronan matrix surrounding the mammalian oocyte

Successful ovulation and oocyte fertilization are essential prerequisites for the beginning of life in sexually reproducing animals. In mammalian fertilization, the relevance of the protein coat surrounding the oocyte plasma membrane, known as zona pellucida, has been widely recognized, while, until not too long ago, the general belief was that the cumulus oophorus, consisting of follicle cells embedded in a hyaluronan rich extracellular matrix, was not essential. This opinion was based on in vitro fertilization procedures, in which a large number of sperms are normally utilized and the oocyte can be fertilized even if depleted of cumulus cells. Conversely, in vivo, only very few sperm cells reach the fertilization site, arguing against the possibility of a coincidental encounter with the oocyte. In the last two decades, proteins required for HA organization in the cumulus extracellular matrix have been identified and the study of fertility in mice deprived of the corresponding genes have provided compelling evidence that this jelly-like coat is critical for fertilization. This review focuses on the advances in understanding the molecular interactions making the cumulus environment suitable for oocyte and sperm encounter. Most of the studies on the molecular characterization of the cumulus extracellular matrix have been performed in the mouse and we will refer essentially to findings obtained in this animal model.

The Biological Role of Hyaluronan-Rich Oocyte-Cumulus Extracellular Matrix in Female Reproduction

Fertilization of the mammalian oocyte requires interactions between spermatozoa and expanded cumulus extracellular matrix (ECM) that surrounds the oocyte. This review focuses on key molecules that play an important role in the formation of the cumulus ECM, generated by the oocyte-cumulus complex. In particular, the specific inhibitors (AG1478, lapatinib, indomethacin and MG132) and progesterone receptor antagonist (RU486) exerting their effects through the remodeling of the ECM of the cumulus cells surrounding the oocyte have been described. After gonadotropin stimulus, cumulus cells expand and form hyaluronan (HA)-rich cumulus ECM. In pigs, the proper structure of the cumulus ECM depends on the interaction between HA and serum-derived proteins of the inter-alpha-trypsin inhibitor (IαI) protein family. We have demonstrated the synthesis of HA by cumulus cells, and the presence of the IαI, tumor necrosis factor-alpha-induced protein 6 and pentraxin 3 in expanding oocyte-cumulus complexes (OCC). We have evaluated the covalent linkage of heavy chains of IαI proteins to HA, as the principal component of the expanded HA-rich cumulus ECM, in porcine OCC cultured in medium with specific inhibitors: AG1478 and lapatinib (both inhibitors of epidermal growth factor receptor tyrosine kinase activity); MG132 (a specific proteasomal inhibitor), indomethacin (cyclooxygenase inhibitor); and progesterone receptor antagonist (RU486). We have found that both RU486 and indomethacin does not disrupt the formation of the covalent linkage between the heavy chains of IαI to HA in the expanded OCC. In contrast, the inhibitors AG1478 and lapatinib prevent gonadotropin-induced cumulus expansion. Finally, the formation of oocyte-cumulus ECM relying on the covalent transfer of heavy chains of IαI molecules to HA has been inhibited in the presence of MG132.

ITIH5 induces a shift in TGF-β superfamily signaling involving Endoglin and reduces risk for breast cancer metastasis and tumor death

ITIH5 has been proposed being a novel tumor suppressor in various tumor entities including breast cancer. Recently, ITIH5 was furthermore identified as metastasis suppressor gene in pancreatic carcinoma. In this study we aimed to specify the impact of ITIH5 on metastasis in breast cancer. Therefore, DNA methylation of ITIH5 promoter regions was assessed in breast cancer metastases using the TCGA portal and methylation-specific PCR (MSP). We reveal that the ITIH5 upstream promoter region is particularly responsible for ITIH5 gene inactivation predicting shorter survival of patients. Notably, methylation of this upstream ITIH5 promoter region was associated with disease progression, for example, abundantly found in distant metastases. In vitro, stably ITIH5-overexpressing MDA-MB-231 breast cancer clones were used to analyze cell invasion and to identify novel ITIH5-downstream targets. Indeed, ITIH5 re-expression suppresses invasive growth of MDA-MB-231 breast cancer cells while modulating expression of genes involved in metastasis including Endoglin (ENG), an accessory TGF-β receptor, which was furthermore co-expressed with ITIH5 in primary breast tumors. By performing in vitro stimulation of TGF-β signaling using TGF-β1 and BMP-2 we show that ITIH5 triggered a TGF-β superfamily signaling switch contributing to downregulation of targets like Id1, known to endorse metastasis. Moreover, ITIH5 predicts longer overall survival (OS) only in those breast tumors that feature high ENG expression or inversely regulated ID1 suggesting a clinical and functional impact of an ITIH5-ENG axis for breast cancer progression. Hence, we provide evidence that ITIH5 may represent a novel modulator of TGF-β superfamily signaling involved in suppressing breast cancer metastasis.

The Wilms tumor protein Wt1 contributes to female fertility by regulating oviductal proteostasis

Although the zinc finger transcription factor Wt1 has been linked to female fertility, its precise role in this process has not yet been understood. We have sequenced the WT1 exons in a panel of patients with idiopathic infertility and have identified a missense mutation in WT1 in one patient out of eight. This mutation leads to an amino acid change within the zinc finger domain and results in reduced DNA binding. We utilized Wt1^+/- mice as a model to mechanistically pinpoint the consequences of reduced Wt1 levels for female fertility. Our results indicate that subfertility in Wt1^+/- female mice is a maternal effect caused by the Wt1-dependent de-regulation of Prss29, encoding a serine protease. Notably, blocking Prss29 activity was sufficient to rescue subfertility in Wt1^+/- mice indicating Prss29 as a critical factor in female fertility. Molecularly, Wt1 represses expression of Prss29. De-repression and precocious expression of Prss29 in the oviduct of Wt1^+/- mice interferes with pre-implantation development. Our study reveals a novel role for Wt1 in early mammalian development and identifies proteases as critical mediators of the maternal-embryonic interaction. Our data also suggest that the role of Wt1 in regulating fertility is conserved in mammals.

Genome-wide in vivo RNAi screen identifies ITIH5 as a metastasis suppressor in pancreatic cancer

The overwhelming majority of pancreatic ductal adenocarcinoma (PDAC) is not diagnosed until the cancer has metastasized, leading to an abysmal average life expectancy (3-6 months post-diagnosis). Earlier detection and more effective treatments have been hampered by inadequate understanding of the underlying molecular mechanisms controlling metastasis. We hypothesized that metastasis suppressors are involved in controlling metastasis in pancreatic cancer. Using an unbiased genome-wide shRNA screen, an shRNA library was transduced into the non-metastatic PDAC line S2-028 followed by intrasplenic injection. Resulting liver metastases were individually isolated from these mice. One liver metastatic nodule contained shRNA for ITIH5 (Inter-alpha-trypsin inhibitor heavy chain 5), suggesting that ITIH5 may act as a metastasis suppressor. Consistent with this notion, metastatic PDAC cell lines had significantly lower protein expression of ITIH5 compared to immortalized pancreatic ductal epithelial cells and non-/poorly-metastatic PDAC cell lines. By manipulating expression of ITIH5 in different PDAC cell lines (over-expression in metastatic, knockdown in non-metastatic) functional and selective regulation of metastasis was observed for ITIH5. Orthotopic tumor growth of PDAC cells was not blocked following orthotopic injection. In vitro ITIH5 over-expression inhibited motility and invasion. Immunohistochemical analysis of a human PDAC tissue microarray revealed that ITIH5 expression inversely correlated with both survival and invasion/metastasis. ITIH5 is, therefore, functionally validated as a PDAC metastasis suppressor and shows promise as a prognostic biomarker.

ITIH5 mediates epigenetic reprogramming of breast cancer cells

Background

Extracellular matrix (ECM) is known to maintain epithelial integrity. In carcinogenesis ECM degradation triggers metastasis by controlling migration and differentiation including cancer stem cell (CSC) characteristics. The ECM-modulator inter- α-trypsin inhibitor heavy chain family member five (ITIH5) was recently identified as tumor suppressor potentially involved in impairing breast cancer progression but molecular mechanisms underlying its function are still elusive.

Methods

ITIH5 expression was analyzed using the public TCGA portal. ITIH5-overexpressing single-cell clones were established based on T47D and MDA-MB-231 cell lines. Colony formation, growth, apoptosis, migration, matrix adhesion, traction force analyses and polarization of tumor cells were studied in vitro. Tumor-initiating characteristics were analyzed by generating a metastasis mouse model. To identify ITIH5-affected pathways we utilized genome wide gene expression and DNA methylation profiles. RNA-interference targeting the ITIH5-downstream regulated gene DAPK1 was used to confirm functional involvement.

Results

ITIH5 loss was pronounced in breast cancer subtypes with unfavorable prognosis like basal-type tumors. Functionally, cell and colony formation was impaired after ITIH5 re-expression in both cell lines. In a metastasis mouse model, ITIH5 expressing MDA-MB-231 cells almost completely failed to initiate lung metastases. In these metastatic cells ITIH5 modulated cell-matrix adhesion dynamics and altered biomechanical cues. The profile of integrin receptors was shifted towards β1-integrin accompanied by decreased Rac1 and increased RhoA activity in ITIH5-expressing clones while cell polarization and single-cell migration was impaired. Instead ITIH5 expression triggered the formation of epithelial-like cell clusters that underwent an epigenetic reprogramming. 214 promoter regions potentially marked with either H3K4 and /or H3K27 methylation showed a hyper- or hypomethylated DNA configuration due to ITIH5 expression finally leading to re-expression of the tumor suppressor DAPK1. In turn, RNAi-mediated knockdown of DAPK1 in ITIH5-expressing MDA-MB-231 single-cell clones clearly restored cell motility.

Conclusions

Our results provide evidence that ITIH5 triggers a reprogramming of breast cancer cells with known stem CSC properties towards an epithelial-like phenotype through global epigenetic changes effecting known tumor suppressor genes like DAPK1. Therewith, ITIH5 may represent an ECM modulator in epithelial breast tissue mediating suppression of tumor initiating cancer cell characteristics which are thought being responsible for the metastasis of breast cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-017-0610-2) contains supplementary material, which is available to authorized users.

Follicular fluid biomarkers for human in vitro fertilization outcome: Proof of principle

Background

Human follicular fluid (FF) is a unique biological fluid in which the oocyte develops in vivo, and presents an optimal source for non-invasive biochemical predictors. Oocyte quality directly influences the embryo development and hence, may be used as a predictor of embryo quality. Peptide profiling of FF and its potential use as a biomarker for oocyte quality has never been reported.

Methods

This study screened FF for peptide biomarkers that predict the outcome of in vitro fertilization (IVF). Potential biomarkers were discovered by investigating 2 training datasets, consisting both of 17 samples and validating on an independent experiment containing 32 samples. Peptide profiles were acquired by nano-scale liquid chromatography coupled to tandem mass spectrometry (nano LC-MS/MS).

Results

From the training datasets 53 peptides were found as potential biomarker candidates, predicting the fertilization outcome of 24 out of the 32 validation samples blindly (81.3% sensitivity, 68.8% specificity, AUC = 0.86). Seven potential biomarker peptides were identified. They were derived from: insulin-like growth factor binding protein-5, alpha-2-antiplasmin, complement component 3, inter-alpha-trypsin inhibitor heavy chain H1, serum albumin, protein diaphanous homolog 1 and plastin-3.

Conclusions

The MS-based comprehensive peptidomic approach carried out in this study, established a novel panel of potential biomarkers that present a promising predictive accuracy rate in fertilization outcome, and indicates FF as an interesting biomarker resource to improve IVF clinic routine.

Electronic supplementary material

The online version of this article (doi:10.1186/s12953-016-0106-9) contains supplementary material, which is available to authorized users.

Increased expression of pentraxin 3 after in vivo and in vitro stimulation with gonadotropins in porcine oocyte-cumulus complexes and granulosa cells

It has been previously shown that multimeric pentraxin 3 (PTX3) is a key component of the cumulus oophorus extracellular matrix (ECM) in mice. In response to the ovulatory LH surge, the cumulus cells assemble a unique ECM that envelopes the oocyte and cumulus cell complex. Importantly, cumuli from PTX3(-/-) mice were defective in their ECM organization and their fertility was impaired. It has been demonstrated that tumor necrosis factor alpha-induced protein 6 catalyzes the formation of heavy chains of (inter-alpha-trypsin inhibitor) -hyaluronan complexes and these are then cross-linked via PTX3. This process is tightly regulated and requires the proteins to meet/interact in the correct order. Finally, in this way, the above-listed proteins form the cumulus oophorus ECM. We investigated whether PTX3 is expressed in the porcine preovulatory follicle. Porcine oocyte-cumulus complexes (OCC) and mural granulosa cells (MGC) from gilts were obtained either after stimulation in vivo with eCG/hCG (4, 8, 16, 24, and 32 h) or culture in vitro (4, 24, and 44 h) in FSH/LH-supplemented medium. The methods performed were real-time reverse transcriptase-polymerase chain reaction, Western blot analysis, and immunostaining. The expression of PTX3 transcripts was significantly increased 24 h after either in vivo hCG stimulation or in vitro FSH/LH treatment in both OCC and MGC. Western blot analysis with PTX3 antibody revealed that not only matrix extracts from in vivo-stimulated gilts contain high levels of PTX3 protein but also matrix extracts of FSH/LH-stimulated OCC cultured in medium supplemented either with follicular fluid or with porcine serum. The localization of PTX3 in the cumulus oocyte complex was confirmed by immunostaining. In conclusion, PTX3 is produced by porcine OCC and MGC both in vivo and in vitro with gonadotropin stimuli inducing cumulus expansion.

Gene expression analysis of pig cumulus-oocyte complexes stimulated in vitro with follicle stimulating hormone or epidermal growth factor-like peptides

BACKGROUND

The gonadotropin-induced resumption of oocyte meiosis in preovulatory follicles is preceded by expression of epidermal growth factor (EGF)-like peptides, amphiregulin (AREG) and epiregulin (EREG), in mural granulosa and cumulus cells. Both the gonadotropins and the EGF-like peptides possess the capacity to stimulate resumption of oocyte meiosis in vitro via activation of a broad signaling network in cumulus cells. To better understand the rapid genomic actions of gonadotropins (FSH) and EGF-like peptides, we analyzed transcriptomes of cumulus cells at 3 h after their stimulation.

METHODS

We hybridized aRNA from cumulus cells to a pig oligonucleotide microarray and compared the transcriptomes of FSH- and AREG/EREG-stimulated cumulus cells with untreated control cells and vice versa. The identified over- and underexpressed genes were subjected to functional genomic analysis according to their molecular and cellular functions. The expression pattern of 50 selected genes with a known or potential function in ovarian development was verified by real-time qRT-PCR.

RESULTS

Both FSH and AREG/EREG increased the expression of genes associated with regulation of cell proliferation, cell migration, blood coagulation and extracellular matrix remodeling. FSH alone induced the expression of genes involved in inflammatory response and in the response to reactive oxygen species. Moreover, FSH stimulated the expression of genes closely related to some ovulatory events either exclusively or significantly more than AREG/EREG (AREG, ADAMTS1, HAS2, TNFAIP6, PLAUR, PLAT, and HSD17B7). In contrast to AREG/EREG, FSH also increased the expression of genes coding for key transcription factors (CEBPB, FOS, ID1/3, and NR5A2), which may contribute to the differing expression profiles of FSH- and AREG/EREG-treated cumulus cells.

CONCLUSIONS

The impact of FSH on cumulus cell gene transcription was higher than the impact of EGF-like factors in terms of the number of cell functions affected as well as the number of over- and underexpressed genes. Both FSH and EGF-like factors overexpressed genes involved in the post-ovulatory switch in steroidogenesis and tissue remodelling. However, FSH was remarkably more efficient in the up-regulation of several specific genes essential for ovulation of matured oocytes and also genes that been reported to play an important role in maturation of cumulus-enclosed oocytes in vitro.

Stem cells, progenitor cells, and lineage decisions in the ovary

Exploring stem cells in the mammalian ovary has unleashed a Pandora's box of new insights and questions. Recent evidence supports the existence of stem cells of a number of the different cell types within the ovary. The evidence for a stem cell model producing mural granulosa cells and cumulus cells is strong, despite a limited number of reports. The recent identification of a precursor granulosa cell, the gonadal ridge epithelial-like cell, is exciting and novel. The identification of female germline (oogonial) stem cells is still very new and is currently limited to just a few species. Their origins and physiological roles, if any, are unknown, and their potential to produce oocytes and contribute to follicle formation in vivo lacks robust evidence. The precursor of thecal cells remains elusive, and more compelling data are needed. Similarly, claims of very small embryonic-like cells are also preliminary. Surface epithelial cells originating from gonadal ridge epithelial-like cells and from the mesonephric epithelium at the hilum of the ovary have also been proposed. Another important issue is the role of the stroma in guiding the formation of the ovary, ovigerous cords, follicles, and surface epithelium. Immune cells may also play key roles in developmental patterning, given their critical roles in corpora lutea formation and regression. Thus, while the cellular biology of the ovary is extremely important for its major endocrine and fertility roles, there is much still to be discovered. This review draws together the current evidence and perspectives on this topic.

The concentrations of EGFR, LRG1, ITIH4, and F5 in serum correlate with the number of colonic adenomas in ApcPirc/+ rats

The development of noninvasive methods for early detection of colon cancer is critical for the successful management of this disease. Using a targeted quantitative proteomics technique, we assessed the ability of 12 serum proteins to detect the presence of colonic polyps in the Apc(Pirc) (/+) rat model of familial colon cancer. Serum protein candidates were selected from gene transcripts upregulated in colonic tumors of Apc(Pirc) (/+) rats and from a prior study of serum proteins differentially expressed in mice carrying intestinal adenomas. Proteins were quantified at early stages of polyp formation in a rat cohort monitored longitudinally by colonoscopy over a period of 75 days. Of the 12 proteins monitored at three distinct time points, seven showed differential expression in at least one time point in the serum from Apc(Pirc) (/+) rats compared with wild-type rats. Tumor multiplicity correlated with protein expression changes, and most tumors grew during the study. EGFR, LRG1, ITIH4, and F5 displayed the most robust tumor-associated protein expression changes over time. Receiver operator characteristic analysis using these four proteins resulted in a sensitivity of 100%, a specificity of 80%, and an area under the curve of 0.93 at 135 days of age, when the Pirc rats bore an average of 19 tumors in the colon and seven in the small intestine. The results of this study demonstrate that the quantitative analysis of a panel of serum proteins can detect the presence of early intestinal tumors in a rat model, and provides support for future measurements in humans.

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.

Candidate serum biomarkers for early intestinal cancer using 15N metabolic labeling and quantitative proteomics in the ApcMin/+ mouse

Current screening procedures for colorectal cancer are imperfect and highly invasive and result in increased mortality rates due to low compliance. The goal of the experiments reported herein is to identify potential blood-based biomarkers indicative of early stage intestinal cancers using the ApcMin/+ mouse model of intestinal cancer as an experimental system. Serum proteins from tumor-bearing ApcMin/+ mice were quantitatively compared to tumor-free Apc+/+ wild-type mice via in anima metabolic labeling with 14N/15N-labeled Spirulina algae and an LTQ Orbitrap mass spectrometer. Out of 1116 total serum proteins quantified, this study identified 40 that were differentially expressed and correlated with the increase in intestinal neoplasms. A subset of these differentially expressed proteins underwent a secondary quantitative screen using selected reaction monitoring-mass spectrometry with stable isotope-labeled peptides. Using both quantitative techniques, we identified MGAM and COL1A1 as downregulated and ITIH3 and F5 as upregulated in serum. All but COL1A1 were similarly differentially expressed in the mRNA of neoplastic colonic tissues of ApcMin/+ mice compared to normal wild-type tissue. These differentially expressed proteins identified in the ApcMin/+ mouse model have provided a set of candidate biomarkers for future validation screens in humans.

The blood-follicle barrier (BFB) in disease and in ovarian function

The blood-follicle barrier (BFB) is one of the blood-tissue barriers in mammalian body found in developing follicles in the ovary. The BFB, besides the tight junction (TJ)-permeability barrier of the endothelial cells in the microvessels that surround the developing follicle, is constituted and contributed significantly by the basement membrane of the developing follicle which alters its composition rapidly during follicle development. While the concept of the BFB and its ultrastructure were described more than six decades ago, fewer than 20 reports are found in the literature that were dedicated to investigate the biology, regulation, and function of the BFB either in health or in disease. Furthermore, detailed analysis of the adhesion protein complexes and the regulation of the junction dynamics at the BFB are still missing in the literature. The goal of this short chapter is to provide an update on this important blood-tissue barrier, it is obvious that future investigation is much needed in the field to understand this ultrastructure better in order to treat and better ovarian disorders including ovarian cancer.

Heavy chains of inter alpha inhibitor (IαI) inhibit the human complement system at early stages of the cascade

Inter alpha inhibitor (IαI) is an abundant serum protein consisting of three polypeptides: two heavy chains (HC1 and HC2) and bikunin, a broad-specificity Kunitz-type proteinase inhibitor. The complex is covalently held together by chondroitin sulfate but during inflammation IαI may interact with TNF-stimulated gene 6 protein (TSG-6), which supports transesterification of heavy chains to hyaluronan. Recently, IαI was shown to inhibit mouse complement in vivo and to protect from complement-mediated lung injury but the mechanism of such activity was not elucidated. Using human serum depleted from IαI, we found that IαI is not an essential human complement inhibitor as was reported for mice and that such serum has unaltered hemolytic activity. However, purified human IαI inhibited classical, lectin and alternative complement pathways in vitro when added in excess to human serum. The inhibitory activity was dependent on heavy chains but not bikunin and detected at the level of initiating molecules (MBL, properdin) in the lectin/alternative pathways or C4b in the classical pathway. Furthermore, IαI affected formation and assembly of the C1 complex and prevented assembly of the classical pathway C3-convertase. Presence and putative interactions with TSG-6 did not affect the ability of IαI to inhibit complement thus implicating IαI as a potentially important complement inhibitor once enriched onto hyaluronan moieties in the course of local inflammatory processes. In support of this, we found a correlation between IαI/HC-containing proteins and hemolytic activity of synovial fluid from patients suffering from rheumatoid arthritis.

Constitutive expression of inter-α-inhibitor (IαI) family proteins and tumor necrosis factor-stimulated gene-6 (TSG-6) by human amniotic membrane epithelial and stromal cells supporting formation of the heavy chain-hyaluronan (HC-HA) complex

Recently, we reported HC-HA, a covalent complex formed between heavy chains (HCs) of inter-α-inhibitor (IαI) and hyaluronan (HA) by the catalytic action of tumor necrosis factor (TNF)-stimulated gene-6 (TSG-6), is responsible for human amniotic membrane (AM) anti-inflammatory, anti-scarring, and anti-angiogenic actions. At the present time, the only well characterized source of IαI is serum being produced by the liver. This study showed that AM epithelial and stromal cells and stromal matrix all stained positively for HA, HC 1, 2, and 3, bikunin, and TSG-6. TSG-6 mRNA and protein were constitutively expressed by cultured AM epithelial and stromal cells without being up-regulated by TNF. In serum-free conditions, these cells expressed IαI, leading to the formation of HC-HA complex that contained both HC1 and HC2. In contrast, only HC1 was found in the HC-HA complex purified from AM. Local production of IαI, the HC-TSG-6 intermediate complex, and HC-HA were abolished when cells were treated with siRNA to HC1, HC2, bikunin (all of which impair the biosynthesis of IαI), or TSG-6 but not to HC3. Collectively, these results indicate that AM is another tissue in addition to the liver to constitutively produce IαI and that the HC-HA complex made by this tissue is different from that found at inflammatory sites (e.g. in asthma and arthritis) and in the matrix of the cumulus oocyte complex.

Aberrant DNA hypermethylation of the ITIH5 tumor suppressor gene in acute myeloid leukemia

Epigenetic mechanisms such as DNA hypermethylation and modifications of histone amino acids are known to play an important role in the control of gene expression both in normal human development and tumorigenesis. Hypermethylation of CpG islands within promoter regions of tumor suppressor genes is associated with transcriptional inactivation and represents, in addition to genetic aberrations, an important mechanism of gene silencing in the pathogenesis of human cancer. Inter-α-trypsine inhibitors (ITIs) are a family of serine protease inhibitors consisting of one light chain (bikunin) and two heavy chains (ITI heavy chains, ITIHs). ITIHs stabilize the extracellular matrix (ECM) by interacting with hyaluronic acid, which is a major ECM component. Hypermethylation in the upstream region of the promoter-associated CpG island of ITIH5, the most recently described member of the ITIH family, has been previously detected in breast cancer and was associated with an adverse outcome. In this study, we determined the DNA methylation status of the promoter region near the transcription start site of the ITIH5 tumor suppressor gene in leukemia cell lines and primary samples from patients with acute myeloid leukemia (AML) as well as the potential use of demethylating agents to restore a demethylated state of the promoter. Aberrant ITIH5 promoter hypermethylation occurred in 15 of 104 (14.4%) diagnostic AML samples. There were no statistically significant correlations between the ITIH5 methylation status and clinical prognostic parameters. Our results indicate that aberrant ITIH5 promoter hypermethylation is a novel epigenetic event in AML.

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.

Periovulatory expression of hyaluronan and proteoglycan link protein 1 (Hapln1) in the rat ovary: hormonal regulation and potential function

Periovulatory follicular matrix plays an important role in cumulus-oocyte complex (COC) expansion, ovulation, and luteal formation. Hyaluronan and proteoglycan link protein 1 (HAPLN1), a component of follicular matrix, was shown to enhance COC expansion in vitro. However, the regulatory mechanisms of periovulatory expression of Hapln1 and its role in periovulatory granulosa cells have not been elucidated. We first determined the periovulatory expression pattern of Hapln1 using pregnant mare serum gonadotropin/human chorionic gonadotropin (PMSG/hCG)-primed immature rat ovaries. Hapln1 expression was transiently induced both in intact ovaries and granulosa cells at 8 h and 12 h after hCG injection. This in vivo expression of Hapln1 was recapitulated by culturing preovulatory granulosa cells with hCG. The stimulatory effect of hCG was blocked by inhibition of protein kinase A, phosphatidylinositol-dependent kinase, p38 MAPK, epidermal growth factor signaling, and prostaglandin synthesis, revealing key mediators involved in LH-induced Hapln1 expression. In addition, knockdown of Runx1 and Runx2 expression by small interfering RNA or inhibition of RUNX activities by dominant-negative RUNX decreased hCG or agonist-induced Hapln1 expression. Chromatin immunoprecipitation assays verified the in vivo binding of RUNX1 and RUNX2 to the Hapln1 promoter in periovulatory granulosa cells. Luciferase reporter assays revealed that mutation of the RUNX binding sites completely obliterated the agonist-induced activity of the Hapln1 promoter. These data conclusively identified RUNX proteins as the crucial transcription regulators for LH-induced Hapln1 expression. Functionally, treatment with HAPLN1 increased the viability of cultured granulosa cells and decreased the number of the cells undergoing apoptosis, whereas knockdown of Hapln1 expression decreased granulosa cells viability. This novel finding indicates that HAPLN1 may promote periovulatory granulosa cell survival, which would facilitate their differentiation into luteal cells.

Permselectivity of blood follicle barriers in mouse ovaries of the mifepristone-induced polycystic ovary model revealed by in vivo cryotechnique

Despite the potential association of polycystic ovary (PCO) syndrome with hemodynamic changes, follicular microenvironment and the involvement of blood follicle barriers (BFB), a histopathological examination has been hampered by artifacts caused by conventional preparation methods. In this study, mouse ovaries of a mifepristone-induced PCO model were morphologically and immunohistochemically examined byin vivocryotechnique (IVCT), which prevents those technical artifacts. Ovarian specimens of PCO model mice were prepared by IVCT or the conventional perfusion fixation after s.c. injection of mifepristone. Their histology and immunolocalization of plasma proteins, including albumin (molecular mass, 69 kDa), immunoglobulin G (IgG, 150 kDa), inter-α-trypsin inhibitor (ITI, 220 kDa), fibrinogen (340 kDa), and IgM (900 kDa), were examined. In the PCO model, enlarged blood vessels with abundant blood flow were observed in addition to cystic follicles with degenerative membrana granulosa. The immunolocalization of albumin and IgM in the PCO model were similar to those in normal mice. Albumin immunolocalized in the blood vessels, interstitium or follicles, and IgM was mostly restricted within the blood vessels. In contrast, immunolocalization of IgG, ITI, and fibrinogen changed in the PCO model. Both IgG and ITI were clearly blocked by follicular basement membranes, and hardly observed in the membrana granulosa, though fibrinogen was mostly observed within blood vessels. These findings suggest that increased blood flow and enhanced selectivity of molecular permeation through the BFB are prominent features in the PCO ovaries, and changes in hemodynamic conditions and permselectivity of BFB are involved in the pathogenesis and pathophysiology of PCO syndrome.

Higher expression of hyaluronan binding protein 1 (HABP1/p32/gC1qR/SF2) during follicular development and cumulus oocyte complex maturation in rat

Ovulation is a complex process of releasing a fertilizable oocyte and depends on the proper formation of an extracellular hyaluronan rich matrix by the cumulus oocyte complex (COC). The formation of a HA rich matrix is dependent on the synthesis and organization of HA in the presence of several biomolecules that mediate its crosslinking. To gain an insight into the follicular maturation and COC expansion, we have studied the expression of hyaluronan binding protein 1 (HABP1), which is known to interact specifically with hyaluronan. The level of HABP1 increased markedly during ovulation after gonadotropin stimulation, and the overexpression was seen in mural granulosa cells, expanding cumulus cells and follicular fluid. However, HABP1 could not be detected in the luteal cells of corpus luteum after ovulation. Such increased expression of HABP1 was observed both during in vivo and in vitro conditions of COC expansion. The level of HABP1 transcript was upregulated up to fivefold after COC expansion as compared to compact COC. Immunofluorescence analysis showed HABP1 to be localized in the cytoplasm and extracellular matrix, suggesting its role in ECM organization. The cultured expanded COC treated with hyaluronidase for different time periods showed the gradual dispersion of COC, which coincide with the loss of HABP1 from the matrix suggesting that HABP1 is bound to hyaluronan. These results indicate that HABP1 expressed in rat COCs during maturation may facilitate the formation of the HA matrix in the extracellular space around the oocyte with cumulus expansion during maturation.

The extracellular matrix protein ITIH5 is a novel prognostic marker in invasive node-negative breast cancer and its aberrant expression is caused by promoter hypermethylation

Inter-alpha-trypsin inhibitors (ITIs) are protease inhibitors stabilizing the extracellular matrix. ITIs consist of one light (bikunin) and two heavy chains (ITIHs). We have recently characterized ITIH5, a novel member of the ITIH gene family, and showed that its messenger RNA is lost in a high proportion of breast tumours. In the present study, an ITIH5-specific polyclonal antibody was generated, validated with western blot and used for immunohistochemical analysis on a tissue microarray; ITIH5 was strongly expressed in epithelial cells of normal breast (n=11/15), while it was lost or strongly reduced in 42% (92/217) of invasive breast cancers. ITIH5 expression in invasive carcinomas was associated with positive expression of oestrogen receptor (P=0.008) and histological grade (P=0.024). Correlation of ITIH5 expression with clinical outcome revealed that patients with primary tumours retaining abundant ITIH5 expression had longer recurrence-free survival (RFS; P=0.037) and overall survival (OS; P=0.044), compared to those with reduced expression (mean RFS: 102 vs 78 months; mean OS: 120 vs 105 months). Methylation-specific PCR analysis frequently showed strong methylation of the ITIH5 promoter in primary breast tumours (41%, n=109) and breast cancer cell lines (n=6). Methylation was significantly associated with mRNA loss (P<0.001; n=39), and ITIH5 expression was induced after treatment of tumour cell lines with the demethylating agent 5-aza-2'-deoxycytidine. Moreover, ITIH5 promoter methylation was significantly associated with reduced OS (P=0.008). The cellular function of ITIH5 was evaluated by forced expression of a full-length ITIH5 complementary DNA in the breast cancer cell line MDA-MB-231, which does not endogenously express ITIH5. ITIH5-expressing clones showed a 40% reduced proliferation rate compared to mock-transfected cells. Overall, these data show that promoter methylation-mediated loss of ITIH5 expression is associated with unfavourable outcome in breast cancer patients, and thus ITIH5 could be used as a prognostic marker, although this marker is not multivariate independent due to its close association with ER expression. Our data indicate that ITIH5 is a candidate class II tumour suppressor gene and could be involved in tumour progression, invasion and metastasis, as its absence is associated with increased proliferation rates and a prognostic value indicating poor clinical outcome.

Molecular mechanisms of insulin-like growth factor 1 promoted synthesis and retention of hyaluronic acid in porcine oocyte-cumulus complexes

The purpose of the present study was to elucidate signaling pathways by which insulin like-growth factor 1 (IGF1) promotes FSH-stimulated synthesis and retention of hyaluronic acid (HA) in pig oocyte-cumulus complexes (OCCs) cultured in serum-free medium. We found that IGF1 had no effects on FSH-stimulated production of cAMP and activation of protein kinase A in the OCCs. Immunoblotting with phospho-specific antibodies showed that FSH moderately phosphorylated v-akt murine thymoma viral oncogene homolog (AKT) and mitogen-activated kinase 3 and 1 (MAPK3/1) in cumulus cells. The exposure of OCCs to both FSH and IGF1 resulted in a significant (P < 0.05) increase in AKT and MAPK3/1 phosphorylation. An inhibitor of phosphoinositide-3-kinase (PIK3), LY 294002, significantly (P < 0.05) reduced the IGF1-enhanced phosphorylation of AKT, and inhibitors of AKT (SH6) and MAPK3/1 (U0126) significantly (P < 0.05) decreased the synthesis and retention of HA stimulated by concomitant exposure of OCCs to both FSH and IGF1. The IGF1-promoted synthesis of HA was not accompanied by an increase in the relative abundance of hyaluronan synthase 2 (HAS2) mRNA in the cumulus cells. We conclude that IGF1 promotes the FSH-stimulated synthesis and retention of HA in pig OCCs by PIK3/AKT- and MAPK3/1-dependent mechanisms.

Characterization of hyaluronan cable structure and function in renal proximal tubular epithelial cells

Alteration in the glycosaminoglycan hyaluronan (HA) has been demonstrated in numerous renal diseases. We have demonstrated that renal proximal tubular epithelial cells (PTCs) surround themselves in vitro with HA in an organized pericellular matrix or 'coat', which is associated with cell migration, and also form pericellular HA cable-like structures which modulate PTC-mononuclear leukocytes interactions. The aim of this study was to characterize potential regulatory mechanism in the assembly of PTC-HA into pericellular cables. HA cables are generated by PTCs in the absence of serum. Immunohistochemical analysis demonstrates the incorporation of components of the inter-alpha-inhibitor (IalphaI) family of proteins and versican into HA cables. Addition of an antibody to IalphaI/PalphaI (pre-alpha-inhibitor) inhibits cable formation. In contrast, inhibition of tumor necrosis factor-alpha-stimulated gene 6 (TSG-6) has no effect on cable formation, suggesting that their generation is independent of the known heavy-chain transfer activity of TSG-6. Overexpression of HAS3 is associated with induction of HA cable formation, and also increased incorporation of HA into pericellular coats. Functionally, this resulted in enhanced HA-dependent monocyte binding and cell migration, respectively. Cell surface expression of CD44 and trypsin-released cell-associated HA were increased in HAS3-overexpressing cells. In addition, hyaluronidase (hyal1 and hyal2) and bikunin mRNA expression were increased, whereas PalphaI HC3 mRNA expression was unchanged in the transfected cells. The data demonstrate the importance of IalphaI/PalphaI in cable formation and suggest that expression of HAS3 may be critical for HA cable assembly.

Formation of ovarian follicular fluid may be due to the osmotic potential of large glycosaminoglycans and proteoglycans

During mammalian follicle development, a fluid-filled antrum develops in the avascular centre of the follicle. We investigated the hypothesis that follicular fluid contains osmotically-active molecules, sufficiently large so as to not freely escape the follicular fluid. Such molecules could generate an osmotic differential and thus recruit fluid from the surrounding vascularised stroma into the antrum. Follicular fluid was collected from bovine follicles classified histologically as healthy (n= 4 pools) or atretic (n= 4 pools). Dialysis of the follicular fluid at 300 kDa or 500 kDa resulted in a reduction in colloid osmotic pressure of 35% and 60%, respectively, in fluid from healthy follicles and 29% and 80% from atretic follicles. Digestion of follicular fluid withStreptomyceshyaluronidase, chondroitinase ABC or DNase 1 followed by dialysis resulted in reductions in osmotic pressure of 43%, 53% and 43% respectively for fluids from healthy follicles and 34%, 20% and 31% for atretic follicles. Digestion with collagenase I, proteinase K, heparanase 1 or keratanase had no significant effect on the osmotic pressure of follicular fluid of healthy follicles. Ion exchange and size exclusion, Western blotting and ELISA identified the proteoglycans versican and inter-alpha trypsin inhibitor and the glycosaminoglycan hyaluronan in follicular fluid. We conclude that these molecules or aggregates of them are of sufficient size to contribute to the osmotic potential of follicular fluid and thus recruit fluid into the follicular antrum. DNA may also contribute but it is probably not a component that is regulated for this role.

Smoking and reproduction: the oviduct as a target of cigarette smoke

The oviduct is an exquisitely designed organ that functions in picking-up ovulated oocytes, transporting gametes in opposite directions to the site of fertilization, providing a suitable environment for fertilization and early development, and transporting preimplantation embryos to the uterus. A variety of biological processes can be studied in oviducts making them an excellent model for toxicological studies. This review considers the role of the oviduct in oocyte pick-up and embryo transport and the evidence that chemicals in both mainstream and sidestream cigarette smoke impair these oviductal functions. Epidemiological data have repeatedly shown that women who smoke are at increased risk for a variety of reproductive problems, including ectopic pregnancy, delay to conception, and infertility. In vivo and in vitro studies indicate the oviduct is targeted by smoke components in a manner that could explain some of the epidemiological data. Comparisons between the toxicity of smoke from different types of cigarettes, including harm reduction cigarettes, are discussed, and the chemicals in smoke that impair oviductal functioning are reviewed.

Plasma bikunin: half-life and tissue uptake

Bikunin is a chondroitin sulfate-containing plasma protein synthesized in the liver. In vitro, it has been shown to inhibit proteases and to have additional activities, but its biological function is still unclear. Here we have studied the dynamics of plasma bikunin in rats and mice. A half-life of 7 +/- 2 min was obtained from the time course of the decrease of the plasma level of bikunin following hepatectomy. Clearance experiments with intravenously injected radiolabeled bikunin with or without the chondroitin sulfate chain showed that the polysaccharide had little influence on the elimination rate of the protein. The uptake of bikunin by different tissues was studied using bikunin labeled with the residualizing agent 125I-tyramine cellobiose; 60 min after intravenous injection, 49% of the radioactivity was recovered in the kidneys and 6-11% in the liver, bones, skin, intestine and skeletal muscle. The uptake in the liver was analyzed by intravenous injection of radiolabeled bikunin followed by collagenase perfusion and dispersion of the liver cells. These experiments indicated that bikunin is first trapped extracellularly within the liver before being internalized by the cells.

Epitope Mapping of a Monoclonal Antibody Specific to Bovine Dry Milk

beta-Lactoglobulin (beta-LG) is a bovine milk protein sensitive to thermal denaturation. Previously, we demonstrated that such structural change can be detected by a monoclonal antibody (mAb) specific to denatured beta-LG. In the present study, we show a dramatic increase in beta-LG immunoreactivity when heating raw milk between 70 and 80 degrees C. To map out the specific epitope of beta-LG recognized by this mAb, we used a combined strategy including tryptic and CNBr fragments, chemical modifications (acetylation and carboxymethylation), peptide array containing in situ synthesized peptides, and a synthetic soluble peptide for immunoassays. The antigenic determinant we defined was exactly located within the D strand (residues 66-76) of beta-LG. Circular dichroic spectral analysis shows that carboxymethylation on beta-LG not only resulted in a substantial loss of beta-configuration but also exerted a 10 times increase in immunoreactivity as compared with heated beta-LG. The result suggests that a further disordered structure occurred in beta-LG and thus rendered the mAb recognition. Mutations on each charged residue (three Lys and one Glu) revealed that Lys-69 and Glu-74 were extremely essential in maintaining the antigenic structure. We also show an inverse relationship between the immunoreactivity in heated beta-LG and its binding to retinol or palmitic acid. Most interestingly, pH 9-10, which neutralizes the Lys groups of beta-LG, not only reduced its immunoreactivity but also its binding to palmitic acid implicating a role of Lys-69. Taken together, we concluded that strand D of beta-LG participated in the thermal denaturation between 70 and 80 degrees C and the binding to retinol and palmitic acid. The antigenic and biochemical roles of mAb specific to D strand are discussed in detail.

Cytokine-induced gene expression at the crossroads of innate immunity, inflammation and fertility: TSG-6 and PTX3/TSG-14

Two cytokine-inducible gene products, important in inflammation and infection, also play essential roles in female fertility. One of these is the product of tumor necrosis factor (TNF)-stimulated gene 6 (TSG-6), alternatively termed TNFAIP6 (for TNF-alpha-induced protein 6), originally cloned from diploid human fibroblasts stimulated with TNF. The second is pentraxin 3 (PTX3), also termed TSG-14, originally isolated from TNF-stimulated human fibroblasts and from interleukin-1 (IL-1)-stimulated vascular endothelial cells. TSG-6, which specifically binds to hyaluronan (HA) and to inter-alpha-inhibitor (I alpha I), shows potent anti-inflammatory activity in acute and chronic inflammation, notably in several models of autoimmune arthritis. PTX3 was shown to play an important role in resistance to fungal infection with Aspergillus fumigatus. Both TSG-6 and PTX3 are synthesized in the ovary prior to ovulation, where they become components of an expanding viscoelastic matrix that surrounds the oocyte before its release from the follicle at the ovarian surface. Female mice with a targeted disruption of either the TSG-6 or PTX3 gene show severe defects in fertility.

Down-regulated expression of A disintegrin and metalloproteinase with thrombospondin-like repeats-1 by progesterone receptor antagonist is associated with impaired expansion of porcine cumulus-oocyte complexes

ADAMTS-1, a member of the A disintegrin and metalloproteinase family of proteases, is expressed in rodent follicles via progesterone receptor (PR)-dependent pathways. However, the functional relationship between ADAMTS-1 expression and PR has not been studied extensively in other species. In the present study, we investigated the time-dependent changes in ADAMTS-1 expression in cumulus cells of porcine cumulus-oocyte complexes (COCs), and the roles of ADAMTS-1 in cumulus expansion during in vitro maturation of oocytes. ADAMTS-1 message was not detected in cumulus cells at the time of collection from the follicles. In response to gonadotropins, ADAMTS-1 mRNA was dramatically up-regulated and reached a maximum at 20 h. The level of mature ADAMTS-1 protein increased in a time-dependent manner with a maximum level at 40 h. The induction of ADAMTS-1 mRNA and protein was significantly decreased by the addition of PR antagonist RU486 to the cultures. However, RU486 did not affect the expression of ADAMTS-4 or factors that had been reported to be required for COC expansion (TSG-6, versican, HA synthase-2). COCs cultured with FSH and LH for 40 h exhibited prominent cumulus expansion. The expansion was reduced significantly by the addition of either RU486 or Galardin, a broad-spectrum matrix metalloproteinase inhibitor. These results suggest that the expression and induction of ADAMTS-1 through receptor-mediated action of progesterone in cumulus cells is one of the essential requirements for gonadotropin-regulated cumulus expansion of porcine COCs.

Specificity of the tumor necrosis factor-induced protein 6-mediated heavy chain transfer from inter-alpha-trypsin inhibitor to hyaluronan: implications for the assembly of the cumulus extracellular matrix

The formation of the hyaluronan-rich cumulus extracellular matrix is crucial for female fertility and accompanied by a transesterification reaction in which the heavy chains (HCs) of inter-alpha-trypsin inhibitor (IalphaI)-related proteins are covalently transferred to hyaluronan. Tumor necrosis factor-induced protein-6 (TNFIP6) is essential for this transfer reaction. Female mice deficient in TNFIP6 are infertile due to the lack of a correctly formed cumulus matrix. In this report, we characterize the specificity of TNFIP6-mediated HC transfer from IalphaI to hyaluronan. Hyaluronan oligosaccharides with eight or more monosaccharide units are potent acceptors in the HC transfer, with longer oligosaccharides being somewhat more efficient. Epimerization of the N-acetyl-glucosamine residues to N-acetyl-galactosamines (i.e. in chondroitin) still allows the HC transfer although at a significantly lower efficiency. Sulfation of the N-acetyl-galactosamines in dermatan-4-sulfate or chondroitin-6-sulfate prevents the HC transfer. Hyaluronan oligosaccharides disperse cumulus cells from expanding cumulus cell-oocyte complexes with the same size specificity as their HC acceptor specificity. This process is accompanied by the loss of hyaluronan-linked HCs from the cumulus matrix and the appearance of oligosaccharide-linked HCs in the culture medium. Chondroitin interferes with the expansion of cumulus cell-oocyte complexes only when added with exogenous TNFIP6 before endogenous hyaluronan synthesis starts, supporting that chondroitin is a weaker HC acceptor than hyaluronan. Our data indicate that TNFIP6-mediated HC transfer to hyaluronan is a prerequisite for the correct cumulus matrix assembly and hyaluronan oligosaccharides and chondroitin interfere with this assembly by capturing the HCs of the IalphaI-related proteins.

The receptor tyrosine kinase Ron is expressed in the mouse ovary and regulates inducible nitric oxide synthase levels and ovulation

OBJECTIVE

To determine the reproductive effects in mice of the deletion of the tyrosine kinase domain of the Ron receptor.

DESIGN

Controlled animal studies.

SETTING

Academic research environment.

ANIMAL(S)

Immature mice with deletion of the tyrosine kinase domain of the Ron receptor (TK-/-) at 22-30 days of age and adult black Swiss female mice at 5-6 weeks of age.

INTERVENTION(S)

Hormonal stimulation of immature female TK-/- animals to induce ovulation.

MAIN OUTCOME MEASURE(S)

Ovulation rates measured by counting the total number of cumulus oocyte complexes in the ampullar region of the murine oviduct after hormonal stimulation. Western blot analysis measured murine ovarian protein levels of endothelial and inducible nitric oxide synthase (iNOS). Immunohistochemical analysis localized iNOS in the developing murine ovarian follicle.

RESULT

Immature TK-/- mice (22-30 days) ovulate significantly fewer cumulus oocyte complexes. Western blot analyses demonstrated increased levels of iNOS before and after ovulation compared with controls. Conversely, endothelial nitric oxide synthase levels were similar and remained constant during corresponding time periods. Immunohistochemical analyses demonstrated a significant increase in iNOS staining throughout the ovary in TK-/- mice with a significant amount of iNOS in granulosa cells surrounding the oocyte when compared with controls.

CONCLUSION(S)

The increased level of nitric oxide in the TK-/- mice is likely due to an elevated level of iNOS, which may contribute to a decrease in the size of the ovaries and ovulation rates of immature TK-/- animals.