The effect of TGF-beta receptor binding peptides on smooth muscle cells

IGF-1 Peptide Mimetic-functionalized Hydrogels Enhance MSC Survival and Immunomodulatory Activity

Human mesenchymal stem cells (MSCs) have demonstrated promise when delivered to damaged tissue or tissue defects for their cytokine secretion and inflammation modulation behaviors that can promote repair. Insulin-like growth factor 1 (IGF-1) has been shown to augment MSCs' viability and survival and promote their secretion of cytokines that signal to endogenous cells, in the treatment of myocardial infarction, wound healing, and age-related diseases. Biomaterial cell carriers can be functionalized with growth factor-mimetic peptides to enhance MSC function while promoting cell retention and minimizing off-target effects seen with direct administration of soluble growth factors. Here, we functionalized alginate hydrogels with three distinct IGF-1 peptide mimetics and the integrin-binding peptide, cyclic RGD. One IGF-1 peptide mimetic (IGM-3) was found to activate Akt signaling and support survival of serum-deprived MSCs. MSCs encapsulated in alginate hydrogels that presented both IGM-3 and cRGD showed a significant reduction in pro-inflammatory cytokine secretion when challenged with interleukin-1β. Finally, MSCs cultured within the cRGD/IGM-3 hydrogels were able to blunt pro-inflammatory gene expression of human primary cells from degenerated intervertebral discs. These studies indicate the potential to leverage cell adhesive and IGF-1 growth factor peptide mimetics together to control therapeutic secretory behavior of MSCs.

Significance Statement

Insulin-like growth factor 1 (IGF-1) plays a multifaceted role in stem cell biology and may promote proliferation, survival, migration, and immunomodulation for MSCs. In this study, we functionalized alginate hydrogels with integrin-binding and IGF-1 peptide mimetics to investigate their impact on MSC function. Embedding MSCs in these hydrogels enhanced their ability to reduce inflammatory cytokine production and promote anti-inflammatory gene expression in cells from degenerative human intervertebral discs exposed to proteins secreted by the MSC. This approach suggests a new way to retain and augment MSC functionality using IGF-1 peptide mimetics, offering an alternative to co-delivery of cells and high dose soluble growth factors for tissue repair and immune- system modulation.

Thermosensitive and antioxidant wound dressings capable of adaptively regulating TGFβ pathways promote diabetic wound healing

Various therapies have been utilized for treating diabetic wounds, yet current regiments do not simultaneously address the key intrinsic causes of slow wound healing, i.e., abnormal skin cell functions (particularly migration), delayed angiogenesis, and chronic inflammation. To address this clinical gap, we develop a wound dressing that contains a peptide-based TGFβ receptor II inhibitor (PTβR2I), and a thermosensitive and reactive oxygen species (ROS)-scavenging hydrogel. The wound dressing can quickly solidify on the diabetic wounds following administration. The released PTβR2I inhibits the TGFβ1/p38 pathway, leading to improved cell migration and angiogenesis, and decreased inflammation. Meanwhile, the PTβR2I does not interfere with the TGFβ1/Smad2/3 pathway that is required to regulate myofibroblasts, a critical cell type for wound healing. The hydrogel's ability to scavenge ROS in diabetic wounds further decreases inflammation. Single-dose application of the wound dressing significantly accelerates wound healing with complete wound closure after 14 days. Overall, using wound dressings capable of adaptively modulating TGFβ pathways provides a new strategy for diabetic wound treatment.

Upregulation of TGF-β type II receptor in high glucose-induced vascular smooth muscle cells

BACKGROUND

Mortality in patients with diabetes mellitus is estimated above 65% due to cardiovascular diseases. The aim of study was to investigate the effects of high-glucose conditions on TGF-β type II receptor (TGFBR2) expression levels, cell viability, and migration rate in vascular smooth muscle cells (VSMCs).

METHODS

VSMCs were incubated in 30 mM and 50 mM of glucose for 24 h, 48 h, and 72 h periods. The gene and protein expression levels were investigated by Real-time qRT-PCR and western blotting techniques, respectively. The cell viability was evaluated by MTT assay. VSMC migration rate was also studied by wound healing assay.

RESULTS

The TGFBR2 gene and protein expression levels were significantly upregulated in all the groups treated with glucose in 24 h, 48 h, and 72 h periods. The cell viability was not significantly affected in values of 30 mM and 50 mM of glucose. The increase of migration rate of VSMCs was not significant.

CONCLUSION

The results suggested the increased expression levels of TGFBR2 in the response to high glucose conditions may modulate the cellular events through the signaling pathway network in VSMCs.

Bacteriophage-based biomaterials for tissue regeneration

Bacteriophage, also called phage, is a human-safe bacteria-specific virus. It is a monodisperse biological nanostructure made of proteins (forming the outside surface) and nucleic acids (encased in the protein capsid). Among different types of phages, filamentous phages have received great attention in tissue regeneration research due to their unique nanofiber-like morphology. They can be produced in an error-free format, self-assemble into ordered scaffolds, display multiple signaling peptides site-specifically, and serve as a platform for identifying novel signaling or homing peptides. They can direct stem cell differentiation into specific cell types when they are organized into proper patterns or display suitable peptides. These unusual features have allowed scientists to employ them to regenerate a variety of tissues, including bone, nerves, cartilage, skin, and heart. This review will summarize the progress in the field of phage-based tissue regeneration and the future directions in this field.

TGF-β1 in Vascular Wall Pathology: Unraveling Chronic Venous Insufficiency Pathophysiology

Chronic venous insufficiency and varicose veins occur commonly in affluent countries and are a socioeconomic burden. However, there remains a relative lack of knowledge about venous pathophysiology. Various theories have been suggested, yet the molecular sequence of events is poorly understood. Transforming growth factor-beta one (TGF-β1) is a highly complex polypeptide with multifunctional properties that has an active role during embryonic development, in adult organ physiology and in the pathophysiology of major diseases, including cancer and various autoimmune, fibrotic and cardiovascular diseases. Therefore, an emphasis on understanding its signaling pathways (and possible disruptions) will be an essential requirement for a better comprehension and management of specific diseases. This review aims at shedding more light on venous pathophysiology by describing the TGF-β1 structure, function, activation and signaling, and providing an overview of how this growth factor and disturbances in its signaling pathway may contribute to specific pathological processes concerning the vessel wall which, in turn, may have a role in chronic venous insufficiency.

Phage Display Technology in Biomaterials Engineering: Progress and Opportunities for Applications in Regenerative Medicine

The field of regenerative medicine has been gaining momentum steadily over the past few years. The emphasis in regenerative medicine is to use various in vitro and in vivo approaches that leverage the intrinsic healing mechanisms of the body to treat patients with disabling injuries and chronic diseases such as diabetes, osteoarthritis, and degenerative disorders of the cardiovascular and central nervous system. Phage display has been successfully employed to identify peptide ligands for a wide variety of targets, ranging from relatively small molecules (enzymes, cell receptors) to inorganic, organic, and biological (tissues) materials. Over the past two decades, phage display technology has advanced tremendously and has become a powerful tool in the most varied fields of research, including biotechnology, materials science, cell biology, pharmacology, and diagnostics. The growing interest in and success of phage display libraries is largely due to its incredible versatility and practical use. This review discusses the potential of phage display technology in biomaterials engineering for applications in regenerative medicine.

Differential effects of a soluble or immobilized VEGFR-binding peptide

Regulating endothelial cell behavior is a key step in understanding and controlling neovascularization for both pro-angiogenic and anti-angiogenic therapeutic strategies. Here, we characterized the effects of a covalently immobilized peptide mimic of vascular endothelial growth factor, herein referred to as VEGF receptor-binding peptide (VR-BP), on human umbilical vein endothelial cell (HUVEC) behavior. Self-assembled monolayer arrays presenting varied densities of covalently immobilized VR-BP and varied densities of the fibronectin-derived cell adhesion peptide Gly-Arg-Gly-Asp-Ser-Pro (GRGDSP) were used to probe for changes in HUVEC attachment, proliferation and tubulogenesis. In a soluble form, VR-BP exhibited pro-angiogenic effects in agreement with previous studies, indicated by increases in HUVEC proliferation. However, when presented to cells in an insoluble context, covalently immobilized VR-BP inhibited several pro-angiogenic HUVEC behaviors, including attachment and proliferation, and also inhibited HUVEC response to soluble recombinant VEGF protein. Furthermore, substrates with covalently immobilized VR-BP also modulated HUVEC tubulogenesis when a matrigel overlay assay was used to provide cells with a pseudo-three dimensional environment. Taken together, these results demonstrate that the context in which ligands are presented to cell surface receptors strongly influences their effects, and that the same ligand can be an agonist or an antagonist depending on the manner of presentation to the cell.

Varicose veins: role of mechanotransduction of venous hypertension

Varicose veins affect approximately one-third of the adult population and result in significant psychological, physical, and financial burden. Nevertheless, the molecular pathogenesis of varicose vein formation remains unidentified. Venous hypertension exerted on veins of the lower extremity is considered the principal factor in varicose vein formation. The role of mechanotransduction of the high venous pressure in the pathogenesis of varicose vein formation has not been adequately investigated despite a good progress in understanding the mechanomolecular mechanisms involved in transduction of high blood pressure in the arterial wall. Understanding the nature of the mechanical forces, the mechanosensors and mechanotransducers in the vein wall, and the downstream signaling pathways will provide new molecular targets for the prevention and treatment of varicose veins. This paper summarized the current understanding of mechano-molecular pathways involved in transduction of hemodynamic forces induced by blood pressure and tries to relate this information to setting of venous hypertension in varicose veins.

Smad2 and PEA3 cooperatively regulate transcription of response gene to complement 32 in TGF-β-induced smooth muscle cell differentiation of neural crest cells

Response gene to complement 32 (RGC-32) is activated by transforming growth factor- β (TGF-β) and plays an important role in smooth muscle cell (SMC) differentiation from neural crest Monc-1 cells. The molecular mechanism governing TGF-β activation of RGC-32, however, remains to be determined. The present studies indicate that TGF-β regulates RGC-32 gene transcription. Sequence analysis revealed a Smad binding element (SBE) located in the region from -1344 to -1337 bp upstream of the transcription start site of RGC-32 gene. A polyomavirus enhancer activator (PEA3) binding site is adjacent to the SBE. Mutation at either SBE or PEA3 site significantly inhibited RGC-32 promoter activity. Mutations at both sites completely abolished TGF-β-induced promoter activity. Biochemically, TGF-β stimulated recruitment of Smad2, Smad4, and PEA3 to the RGC-32 promoter, as revealed by gel shift and chromatin immunoprecipitation analyses. Functionally, Smad2, but not Smad3, activated RGC-32 promoter. PEA3 appeared to enhance Smad2 activity. In agreement with their function, Smad2, but not Smad3, physically interacted with PEA3. In TGF-β-induced SMC differentiation of Monc-1 cells, knockdown of Smad2 by short hairpin RNA resulted in downregulation of RGC-32 and SMC marker genes. The downregulation of SMC markers, however, was rescued by exogenously introduced RGC-32. These results demonstrate that Smad2 regulation of RGC-32 transcription is essential for SMC differentiation from neural crest cells.

IGF-1 has plaque-stabilizing effects in atherosclerosis by altering vascular smooth muscle cell phenotype

Insulin-like growth factor-1 (IGF-1) signaling is important for the maintenance of plaque stability in atherosclerosis due to its effects on vascular smooth muscle cell (vSMC) phenotype. To investigate this hypothesis, we studied the effects of the highly inflammatory milieu of the atherosclerotic plaque on IGF-1 signaling and stability-related phenotypic parameters of murine vSMCs in vitro, and the effects of IGF-1 supplementation on plaque phenotype in an atherosclerotic mouse model. M1-polarized, macrophage-conditioned medium inhibited IGF-1 signaling by ablating IGF-1 and increasing IGF-binding protein 3, increased vSMC apoptosis, and decreased proliferation. Expression of α-actin and col3a1 genes was strongly attenuated by macrophage-conditioned medium, whereas expression of matrix-degrading enzymes was increased. Importantly, all of these effects could be corrected by supplementation with IGF-1. In vivo, treatment with the stable IGF-1 analog Long R3 IGF-1 in apolipoprotein E knockout mice reduced stenosis and core size, and doubled cap/core ratio in early atherosclerosis. In advanced plaques, Long R3 IGF-1 increased the vSMC content of the plaque by more than twofold and significantly reduced the rate of intraplaque hemorrhage. We believe that IGF-1 in atherosclerotic plaques may have a role in preventing plaque instability, not only by modulating smooth muscle cell turnover, but also by altering smooth muscle cell phenotype.

A genetic polymorphism in transforming growth factor beta receptor-2 is associated with serum osteopontin

Osteopontin (OPN) is a secreted glycoprotein demonstrated to play an important role in inflammation. Transforming growth factor beta and a related signalling pathway have been implicated in control of OPN secretion. We examined the relationship between transforming growth factor beta receptor-1 and -2 (TGFBR1 and 2) single nucleotide polymorphisms (SNP) and serum OPN in 296 men from the Health in Men Study. Serum concentrations of OPN and 58 SNPs for TGFBR1 and 2 were assessed. One SNP in TGFBR2 was associated with serum OPN (TGFBR2 g.20690C>T, SNP ID rs4522809, P = 0.0007) after adjusting for multiple testing. This study suggests that polymorphism in TGFBR2 are associated with altered secretion of OPN, supporting a role for transforming growth factor beta in OPN production.

Identification of an Internalising Peptide in Differentiated Calu-3 Cells by Phage Display Technology; Application to Gene Delivery to the Airways

Differentiated, human submucosal-gland carcinoma, Calu-3 cell monolayers were used as in vitro model for the airway epithelium. Internalised phage were selected from a recombinant pComb8 phage library by repetitive cycles of bio-panning on Calu-3 monolayers, protease K degradation, cell-lysis and amplification. After four selection rounds, sequence analysis of 15 enriched phage colonies revealed two clones of 73 and 27% abundancy, named IB1 and IB2, respectively. The IB2 sequence was eliminated due to a frame shift. IB1-phage internalisation at 4 degrees C was significantly lower (P < 0.05) than at 37 degrees C, suggesting involvement of a receptor-mediated endocytosis pathway. The IB1 peptide was synthesised, biotinylated and complexed to streptavidin. IB1/streptavidin-complexes co-administrated with PEI/DNA-polyplexes, enhanced polyplex transfection efficiency, dose dependently, by 6- and 4-fold in Calu-3 cells. IB1/Alexa488-streptavidin complexes were used for confocal laser-scanning microscopy (CLSM) visualisation and showed basolateral localisation in membrane associated and internalising vesicles. This study demonstrates the potential of phage display technology for identification of internalising peptide-epitopes that can enhance gene delivery efficiency in differentiated airway epithelial cells.

Phage peptide display

Molecular imaging is at the forefront in the advancement of in-vivo diagnosis and monitoring of cancer. New peptide-based molecular probes to facilitate cancer detection are rapidly evolving. Peptide-based molecular probes that target apoptosis, angiogenesis, cell signaling and cell adhesion events are in place. Bacteriophage (phage) display technology, a molecular genetic approach to ligand discovery, is commonly employed to identify peptides as tumor-targeting molecules. The peptide itself may perhaps have functional properties that diminish tumor growth or metastasis. More often, a selected peptide is chemically synthesized, coupled to a radiotracer or fluorescent probe, and utilized in the development of new noninvasive molecular imaging probes. A myriad of peptides that bind cancer cells and cancer-associated antigens have been reported from phage library selections. Phage selections have also been performed in live animals to obtain peptides with optimal stability and targeting properties in vivo. To this point, few in-vitro, in-situ, or in-vivo selected peptides have shown success in the molecular imaging of cancer, the notable exception being vascular targeting peptides identified via in-vivo selections. The success of vasculature targeting peptides, such as those with an RGD motif that bind alpha(v)beta(3)integrin, may be due to the abundance and expression patterns of integrins in tumors and supporting vasculature. The discovery of molecular probes that bind tumor-specific antigens has lagged considerably. One promising means to expedite discovery is through the implementation of selected phage themselves as tumor-imaging agents in animals.

TGF-beta-like transcriptional effects of thyroglobulin (Tg) in mouse mesangial cells

TGF-beta-like activities of proteins unrelated to the cytokine could mimic its actions in fibrosis and cell proliferation. Thyroglobulin (Tg) has been identified as having a TGF-beta receptor (TGFbetaR)-binding activity and is deposited in the glomerulus in certain immune-complex diseases. The aim of the present study is to determine whether Tg can reproduce the transcriptional activity of TGF-beta1 in the mouse glomerular mesangial cell (MC), and to examine whether such activity is manifested through TGFbetaR. Real-time RT-PCR was employed to examine the effects of TGF-beta1 and bovine Tg on the expression of three genes (TGF-beta1, plasminogen activator inhibitor 1 [PAI-1], and Pax-8) regulated by TGF-beta1 in other cell types. In addition, a pentacosapeptide TGF-beta1 antagonist, beta(1)(25) (41-65) was employed to determine whether the transcriptional activity of Tg was mediated through the TGF-beta binding site on the TGFbetaR. A 6h exposure to TGF-beta1 resulted in increased TGF-beta1 and PAI-1 transcript, and a decrease in Pax-8. Similarly, a 6h exposure to Tg resulted in increases of about 5-fold in TGF-beta1 and PAI-1 mRNA and a decrease of 53% in Pax-8. In comparison with other proteins, Tg had the greatest positive effect on TGF-beta1 transcript levels. beta(1)(25) (41-65) significantly reduced the TGF-beta1-, but not the Tg-induced changes in TGF-beta1, PAI-1 and Pax-8 transcript levels. We conclude from these studies that Tg possesses a TGF-beta-mimetic transcriptional activity in the MC that is not mediated by its binding to TGFbetaR. These results suggest that Tg and other proteins could initiate glomerular injury by reproducing the actions of TGF-beta1 in the mesangial cell.

TGF-beta1 upregulation in the aging varicose vein

BACKGROUND

Although the etiology of venous insufficiency is not well understood, immune response and aging are beginning to emerge as contributing factors. Factors involved in tissue remodeling such as TGF-beta(1) also seem to play an important role in extracellular matrix production. The aim of this study was to explore the relationship between chronic venous insufficiency and TGF-beta(1) examining the latent/mature form of TGF-beta(1) and the presence of mast cells. Effects of age were also evaluated.

METHODS

Saphenous veins were obtained from patients subjected to aortocoronary bypass (controls) and undergoing varicose vein surgery. These were immunolabeled using anti-LAP TGF-beta(1)/anti-TGF-beta(1) antibodies and subjected to Western blot. Mast cell population was identified by metachromatic staining.

RESULTS

Latent TGF-beta(1) was significantly reduced in varicose veins from older subjects. In contrast, smooth muscle cells obtained from the varicosities showed intense levels. Mature TGF-beta(1) significantly differed between healthy and varicose veins. No mature TGF-beta(1) was detected in the cell cultures. Mast cell number and degranulation were increased with aging and varicose disease, colocalizing with the mature form of TGF-beta(1).

CONCLUSION

Aging and varicose pathology induce dysregulation of TGF-beta(1) that could play an important role in the fibrous process, representing the final stages of venous insufficiency.

Effect of platelet-rich plasma on migration and proliferation of SaOS-2 osteoblasts: role of platelet-derived growth factor and transforming growth factor-beta

Platelet-enriched plasma (PRP) is used in therapy as a source of growth factors in bone fracture and wound healing; however, few data exist on its role in the different aspects of the healing process. The effect of PRP and of the two main growth factors present in this preparation (platelet-derived growth factor [PDGF] and transforming growth factor-beta [TGF-beta]) was evaluated in vitro using the human osteoblastic cell line SaOS-2, which was shown by reverse transcription-polymerase chain reaction to express both PDGF-alpha and -beta receptors. Batroxobine-activated PRP was added in different concentrations to SaOS-2 cells to assess cell migration (by a microchemotaxis assay) and cell proliferation (by [3H]-thymidine incorporation into the DNA). Immunoneutralization with anti-PDGF-beta or anti-TGF-beta antibodies allowed the assessment of the specific role of these growth factors. The overall results obtained indicate that PRP dose-dependently stimulates both chemotaxis and cell proliferation. PDGF and TGF-beta appear to exert distinct effects on the two parameters, the former involved in stimulating cell migration and the latter in inhibiting cell proliferation. It is concluded that the different growth factors present in activated PRP can specifically contribute to the main processes of tissue regeneration.

Overexpression of transforming growth factor-beta1 correlates with increased synthesis of nitric oxide synthase in varicose veins

INTRODUCTION

Transforming growth factor-beta 1 (TGF-beta 1 ) is known to maintain a balance between apoptosis and cellular dysfunction and therefore may have a pivotal role in vessel remodeling during pathogenesis of vascular disorders. We previously demonstrated that inducible nitric oxide synthase (iNOS) mediates signal transduction in vascular wall during the development of varicose veins. Currently, we investigated the expression and correlation of TGF-beta 1 , iNOS, monocyte/macrophage infiltration, and loss of vascular smooth muscle cells (VSMCs), in a series of normal and varicose vein specimens.

METHODS

Twenty varicose vein specimens were retrieved from 20 patients undergoing lower-extremity varicose vein excision, and 27 normal greater saphenous vein segments (controls) were obtained from 27 patients undergoing infrainguinal arterial bypass surgery. Principal risk factors (diabetes mellitus, hypertension, tobacco abuse) were also compared. Varicose vein segments were separated into tortuous and nontortuous regions based on their macroscopic and microscopic morphology. VSMC actin, CD68 + monocytes/macrophages, iNOS, and TGF-beta 1 , were examined by immunohistochemistry, immunoblotting, and real-time reverse transcriptase polymerase chain reaction.

RESULTS

According to the CEAP classification for chronic lower extremity venous disease, most of the patients were in class 2 for clinical signs of the disease (n = 11). Mean ages were 53.6 +/- 4.7 years for the varicose vein group and 56.5 +/- 4.4 years for the controls. The gender distribution was same in both groups. Immunoreactivity to TGF-beta 1 and iNOS was significantly different in the tortuous regions of the varicose veins compared with nontortuous regions (P < .01). Not only was a significantly higher expression of iNOS noted in the varicose vein group (P < .001), but a differential expression of iNOS was also observed in the tortuous and nontortuous portions of the varicose veins. Significant overexpression of TGF-beta 1 (P < .01) that correlated with overproduction of iNOS and with increased presence of CD68 + monocytes/macrophages was observed in the varicose vein walls compared with normal veins.

CONCLUSIONS

This is the first evidence of TGF-beta 1 , as well as iNOS, being differentially upregulated in nontortuous and tortuous segments of varicose veins. The increased expression of TGF-beta 1 and presence of macrophages, correlating with overproduction of iNOS, may be associated with varicosity development and deserves further study.

CLINICAL RELEVANCE

The pathogenesis of varicose veins, the most common manifestation of chronic venous disease, is debatable. Elucidation of mechanisms involved in the disease process is the first step to improved therapeutic modulations. Towards this goal, the relationship between NO production and TGF-beta 1 in the molecular pathophysiology of chronic venous disease was investigated. The data identify for the first time, an important role for TGF-b1-iNOS-monocyte/macrophage signaling in the etiology of varicosities. Furthermore, we determine if there are any significant differences within the varicose vein group itself based on regional differences, by classifying the varicose tissues into tortuous and non-tortuous segments.

Phage display of random peptide libraries: applications, limits, and potential

The identification of ligands from large biological libraries by phage display has now been used for almost 15 years. Most of the successful reports on high-affinity ligand identification originated from work with different antibody libraries. In contrast, the progress of applying phage display to random peptide libraries was relatively slow. However, in the last few years several improvements have led to an increasing number of published peptide ligands identified by phage display from such libraries and which exhibited good biological activity and high affinity. This review summarizes the current state and the technical progress of the application of random peptide libraries using filamentous phage for ligand identification.

Altered bleomycin-induced lung fibrosis in osteopontin-deficient mice

Osteopontin is a multifunctional matricellular protein abundantly expressed during inflammation and repair. Osteopontin deficiency is associated with abnormal wound repair characterized by aberrant collagen fibrillogenesis in the heart and skin. Recent gene microarray studies found that osteopontin is abundantly expressed in both human and mouse lung fibrosis. Macrophages and T cells are known to be major sources of osteopontin. During lung fibrosis, however, osteopontin expression continues to increase when inflammation has receded, suggesting alternative sources of ostepontin during this response. In this study, we demonstrate immunoreactivity for osteopontin in lung epithelial and inflammatory cells in human usual interstitial pneumonitis and murine bleomycin-induced lung fibrosis. After treatment with bleomycin, osteopontin-null mice develop lung fibrosis characterized by dilated distal air spaces and reduced type I collagen expression compared with wild-type controls. There is also a significant decrease in levels of active transforming growth factor-beta(1) and matrix metalloproteinase-2 in osteopontin null mice. Type III collagen expression and total collagenase activity are similar in both groups. These results demonstrate that osteopontin expression is associated with important fibrogenic signals in the lung and that the epithelium may be an important source of osteopontin during lung fibrosis.

Hepatic expression of cytochrome P450s in hepatocyte nuclear factor 1-alpha (HNF1alpha)-deficient mice

Hepatocyte nuclear factor 1 alpha (HNF1alpha) is a liver enriched homeodomain-containing transcription factor that has been shown to transactivate the promoters of several cytochrome P450 (CYP) genes, including CYP2E1, CYP1A2, CYP7A1, and CYP27, in vitro. In humans, mutations in HNF1alpha are linked to the occurrence of maturity onset diabetes of the young type 3, an autosomal dominant form of non-insulin-dependent diabetes mellitus in which afflicted subjects generally develop hyperglycemia before 25 years of age. Mice lacking HNF1alpha also develop similar phenotypes reminiscent of non-insulin-dependent diabetes mellitus. To investigate a potential role for HNF1alpha in the regulation of CYPs in vivo, the expression of major CYP genes from each family was examined in the livers of mice lacking HNF1alpha. Analysis of CYP gene expression revealed marked reductions in expression of Cyp1a2, Cyp2c29 and Cyp2e1, and a moderate reduction of Cyp3a11. In contrast Cyp2a5, Cyp2b10 and Cyp2d9 expression were elevated. There are also significant changes in the expression of genes encoding CYPs involved in fatty acid and bile acid metabolism characterized by a reduction in the expression of Cyp7b1, and Cyp27 as well as elevations in Cyp4a1/3, Cyp7a1, Cyp8b1, and Cyp39a1 expression. These results point to a critical role for HNF1alpha in the regulation of CYPs in vivo and suggest that this transcription factor may have an important influence on drug metabolism as well as lipid and bile acid homeostasis in maturity onset diabetes of the young type 3 diabetics.