Stimulation of glycosaminoglycan synthesis in cultured human dermal fibroblasts by interleukin 1. Induction of hyaluronic acid synthesis by natural and recombinant interleukin 1s and synthetic interleukin 1 beta peptide 163-171

Modulation by 17,20S(OH)2pD of Fibrosis-Related Mediators in Dermal Fibroblast Lines from Healthy Donors and from Patients with Systemic Sclerosis

We previously demonstrated that the non-calcemic pregnacalciferol (pD) analog 17,20S (OH)₂pD suppressed TGF-β1-induced type I collagen production in cultured normal human dermal fibroblasts. In the present studies, we examined fibroblasts cultured from the lesional skin of patients with systemic sclerosis (scleroderma (SSc)) and assessed the effects of 17,20S(OH)₂pD on fibrosis-related mediators. Dermal fibroblast lines were established from skin biopsies from patients with SSc and healthy controls. Fibroblasts were cultured with either 17,20S(OH)₂pD or 1,25(OH)₂D₃ (positive control) with/without TGF-β1 stimulation and extracted for protein and/or mRNA for collagen synthesis and mediators of fibrosis (MMP-1, TIMP-1, PAI-1, BMP-7, PGES, GLI1, and GLI2). 1 7,20S(OH)₂pD (similar to 1,25(OH)₂D₃) significantly suppressed net total collagen production in TGF-β1-stimulated normal donor fibroblast cultures and in cultures of SSc dermal fibroblasts. 17,20S(OH)₂pD (similar to 1,25(OH)₂D₃) also increased MMP-1, BMP-7, and PGES and decreased TIMP-1 and PAI1 expression in SSc fibroblasts. Although 17,20S(OH)₂pD had no effect on Gli1 or Gli2 in SSc fibroblasts, it increased Gli2 expression when cultured with TGF-β1 in normal fibroblasts. These studies demonstrated that 17,20S(OH)₂pD modulates mediators of fibrosis to favor the reduction of fibrosis and may offer new noncalcemic secosteroidal therapeutic approaches for treating SSc and fibrosis.

Paradoxical activation of the protein kinase-transcription factor ERK5 by ERK5 kinase inhibitors

The dual protein kinase-transcription factor, ERK5, is an emerging drug target in cancer and inflammation, and small-molecule ERK5 kinase inhibitors have been developed. However, selective ERK5 kinase inhibitors fail to recapitulate ERK5 genetic ablation phenotypes, suggesting kinase-independent functions for ERK5. Here we show that ERK5 kinase inhibitors cause paradoxical activation of ERK5 transcriptional activity mediated through its unique C-terminal transcriptional activation domain (TAD). Using the ERK5 kinase inhibitor, Compound 26 (ERK5-IN-1), as a paradigm, we have developed kinase-active, drug-resistant mutants of ERK5. With these mutants, we show that induction of ERK5 transcriptional activity requires direct binding of the inhibitor to the kinase domain. This in turn promotes conformational changes in the kinase domain that result in nuclear translocation of ERK5 and stimulation of gene transcription. This shows that both the ERK5 kinase and TAD must be considered when assessing the role of ERK5 and the effectiveness of anti-ERK5 therapeutics.

Synthesis of Hyaluronic Acid by Human Peritoneal Mesothelial Cells: Effect of Cytokines and Dialysa Te

Objective

To assess effects of the inflammatory cytokines (IL-1-beta, TNF-alpha, TGF-beta 1) and dialysate effluent on synthesis of hyaluronic acid by human peritoneal mesothelial cells (HMC) in in vitro culture.

Methods

Dialysate effluent was collected after the overnight dwell of DianeaI 1.5% from patients during CAPD training. HMC were obtained from omentum from nonuremic donors or were harvested from the dialysate effluent from CAPD patients. Synthesis of hyaluronic acid was studied on monolayers of HMC, which were deprived of serum 48 hours priortoexperiment. Effects of cytokines were tested in a medium with low serum concentration (0.1%) or in medium mixed (1:1 v/v) with the autologous dialysate. Hyaluronic acid level in medium was measured with radioimmunoassay.

Results

Cytokines enhanced synthesis of hyaluronic acid by HMC, and the strongest effect was induced by IL-1. Effluent dialysate stimulates synthesis of hyaluronic acid stronger than 10% FCS. Effluent dialysate and IL-1 synergistically enhance synthesis of hyaluronic acid by HMC.

Conclusion

Effluent dialysate from CAPD patients stimulates production of hyaluronic acid by HMC and acts synergistically with cytokines.

Cytoprotective, anti-inflammatory, and antioxidant properties of high-molecular-weight hyaluronan enriched with red orange extract in human fibroblasts exposed to ultra violet light B irradiation

Ultraviolet (UV) light exposure is the primary factor responsible for skin photoaging, affecting all the skin layers, mainly through the production of reactive oxygen species (ROS), activation of inflammatory responses, and apoptosis. In keeping with this evidence, exogenous supplementation with dietary antioxidants has been shown to provide photoprotective benefits. Moreover, oral administration of hyaluronic acid (HA) has been proved to reduce the signs of aged skin, such as wrinkles, and increase hydration and elasticity. The combination of different biologically active substances in order to slow down the onset of skin aging could represent a promising preventive strategy against photoaging. In the present study, we investigated the effects of a dietary supplement (IALUTEC^® RED), consisting of high-molecular-weight HA (HMW-HA) combined with red orange extract (ROC-Red Orange Complex^® ), in human fibroblasts exposed to ultra violet light B-induced oxidative stress. Our study suggests that, in fibroblasts exposed to UVB light, IALUTEC^® RED is active in decreasing both the inflammatory response and the generation of ROS, two events that are involved in skin photoaging.

Pathogenesis of Systemic Sclerosis

Systemic scleroderma (SSc) is one of the most complex systemic autoimmune diseases. It targets the vasculature, connective tissue-producing cells (namely fibroblasts/myofibroblasts), and components of the innate and adaptive immune systems. Clinical and pathologic manifestations of SSc are the result of: (1) innate/adaptive immune system abnormalities leading to production of autoantibodies and cell-mediated autoimmunity, (2) microvascular endothelial cell/small vessel fibroproliferative vasculopathy, and (3) fibroblast dysfunction generating excessive accumulation of collagen and other matrix components in skin and internal organs. All three of these processes interact and affect each other. The disease is heterogeneous in its clinical presentation that likely reflects different genetic or triggering factor (i.e., infection or environmental toxin) influences on the immune system, vasculature, and connective tissue cells. The roles played by other ubiquitous molecular entities (such as lysophospholipids, endocannabinoids, and their diverse receptors and vitamin D) in influencing the immune system, vasculature, and connective tissue cells are just beginning to be realized and studied and may provide insights into new therapeutic approaches to treat SSc.

Cutaneous mucinosis in a strain of brown-egg laying chickens

Cutaneous mucinosis is a cutaneous disorder described in humans, dogs, and rarely cats but never reported in birds. Twenty-six brown egg-laying chickens between ages 43 and 46 weeks had a history of feather loss, scaly, dry skin, weight loss, and decreased egg production. Microscopic findings in the skin included fragmentation of collagen bundles and interstitial, periadnexal, and perivascular dermal accumulation of wispy, mildly basophilic material that was also occasionally observed within the follicular epithelium. A moderate lymphoplasmacytic and heterophilic perivascular dermatitis was also observed. The wispy to granular material was diffusely Alcian blue positive and periodic acid-Schiff negative (consistent with mucin), suggesting a diagnosis of primary or secondary cutaneous mucinosis. The cause of this condition could not be determined.

Gadolinium-based compounds induce NLRP3-dependent IL-1β production and peritoneal inflammation

OBJECTIVE

Nephrogenic systemic fibrosis (NSF) is a progressive fibrosing disorder that may develop in patients with chronic kidney disease after administration of gadolinium (Gd)-based contrast agents (GBCAs). In the setting of impaired renal clearance of GBCAs, Gd deposits in various tissues and fibrosis subsequently develops. However, the precise mechanism by which fibrosis occurs in NSF is incompletely understood. Because other profibrotic agents, such as silica or asbestos, activate the nucleotide-binding oligomerisation domain (NOD)-like receptor protein 3 (NLRP3) inflammasome and initiate interleukin (IL)-1β release with the subsequent development of fibrosis, we evaluated the effects of GBCAs on inflammasome activation.

METHODS

Bone marrow derived macrophages from C57BL/6, Nlrp3(-/-) and Asc(-/-) mice were incubated with three Gd-containing compounds and IL-1β activation and secretion was detected by ELISA and western blot analysis. Inflammasome activation and regulation was investigated in IL-4- and interferon (IFN)γ-polarised macrophages by ELISA, quantitative real time (qRT)-PCR and NanoString nCounter analysis. Furthermore, C57BL/6 and Nlrp3(-/-)mice were intraperitoneally injected with GBCA and recruitment of inflammatory cells to the peritoneum was analysed by fluorescence-activated cell sorting (FACS).

RESULTS

Free Gd and GBCAs activate the NLRP3 inflammasome and induce IL-1β secretion in vitro. Gd-diethylenetriaminepentaacetic acid also induces the recruitment of neutrophils and inflammatory monocytes to the peritoneum in vivo. Gd activated IL-4-polarised macrophages more effectively than IFNγ-polarised macrophages, which preferentially expressed genes known to downregulate inflammasome activity.

CONCLUSIONS

These data suggest that Gd released from GBCAs triggers a NLRP3 inflammasome-dependent inflammatory response that leads to fibrosis in an appropriate clinical setting. The preferential activation of IL-4-differentiated macrophages is consistent with the predominantly fibrotic presentation of NSF.

The decreased secretion of hyaluronan by older human fibroblasts under physiological conditions is mainly associated with the down-regulated expression of hyaluronan synthases but not with the expression levels of hyaluronidases

Although it has been reported that levels of hyaluronan are decreased in the dermis of aged skin, little is known about the cellular mechanism(s) underlying that hyaluronan deficiency. Since hyaluronan is produced by dermal fibroblasts and is secreted into the surrounding dermal tissues, we examined the secretion of hyaluronan by dermal fibroblasts and characterized its cellular mechanism using real-time RT-PCR and western blotting for its synthesizing and degrading enzymes, hyaluronan synthase and hyaluronidase, respectively. The secretion of hyaluronan by dermal fibroblasts derived from differently aged human donors, was higher in the younger human fibroblasts tested (0 and 19 years old) compared to the older human fibroblasts tested (39, 56 and 77 years old). The relative secretion levels of hyaluronan by the different human fibroblasts tested were attributable to the relative expression of hyaluronan synthases 1, 2, 3 but not hyaluronidases 1, 2 enzymes at the gene and protein levels among those fibroblasts. These findings indicate that the deficiency of hyaluronan in the aged dermis might result from the down-regulation in the potential of older human fibroblasts to secrete hyaluronan and that decrease in secretory potential is mainly associated with the down-regulated expression of hyaluronan synthases, especially hyaluronan synthase 2, but not with the expression levels of hyaluronidases.

Isolation and characterization of hyaluronic acid from marine organisms

Hyaluronic acid (HA) being a viscous slippery substance is a multifunctional glue with immense therapeutic applications such as ophthalmic surgery, orthopedic surgery and rheumatology, drug delivery systems, pulmonary pathology, joint pathologies, and tissue engineering. Although HA has been isolated from terrestrial origin (human umbilical cord, rooster comb, bacterial sources, etc.) so far, the increasing interest on this polysaccharide significantly aroused the alternative search from marine sources since it is at the preliminary level. Enthrallingly, marine environments are considered more biologically diverse than terrestrial environments. Although numerous methods have been described for the extraction and purification of HA, the hitch on the isolation methods which greatly influences the yield as well as the molecular weight of the polymer still exists. Adaptation of suitable method is essential in this venture. Stimulated by the developed technology, to sketch the steps involved in isolation and analytical techniques for characterization of this polymer, a brief report on the concerned approach has been reviewed.

Unusual Morphologic Presentations of Blastic Plasmacytoid Dendritic Cell Neoplasm

We present 2 cases of blastic plasmacytoid dendritic cell neoplasm (BPDCN) showing unusual histological features. One patient, a 73-year-old male, presented with a nonpruritic macular erythema of the skin on the anterior and posterior chest wall, the biopsy of which was originally diagnosed as malignant melanoma. The neoplastic cells were negative for S100 and HMB45 and strongly positive for CD45, CD4, CD56, and CD123. The final diagnosis was a BPDCN associated with abundant melanin pigment and numerous melanophages. The second patient was a 73-year-old male with a 5-month history of small, slowly enlarging, bruise-like plaques on his limbs and chest. Histologic examination of the skin biopsy revealed an atypical cellular/myxoid infiltrate with numerous macrophages, which was originally diagnosed as consistent with lepromatous leprosy. The atypical cells were immersed in an alcian blue–positive myxoid matrix at pH 2.5. The Fite-Faraco stain was negative. Positive immunoreactivity was demonstrated for CD4, CD56, and CD123. Based on the histopathology and immunohistochemistry findings, a diagnosis of BPDCN with prominent myxoid matrix was rendered.

20S-hydroxyvitamin D3, noncalcemic product of CYP11A1 action on vitamin D3, exhibits potent antifibrogenic activity in vivo

CONTEXT

There is no effective treatment for systemic sclerosis and related fibrosing diseases. Recently the action of CYP11A1 on vitamin D(3) was shown to produce biologically active 20S-hydroxyvitamin D [20(OH)D(3)] and 20,23(OH)(2)D(3), 20,22(OH)(2)D(3), and 17,20,23(OH)(3)D(3).

OBJECTIVES

Because 20(OH)D(3) is noncalcemic (nontoxic) in vivo at very high doses, we evaluated its antifibrogenic activities both in vitro and in vivo. Because it is further metabolized by CYP11A1, we also tested preclinical utilities of its hydroxyderivatives, especially 20,23(OH)(2)D(3).

DESIGN

Human dermal fibroblasts from scleroderma and normal donors were used to test the efficiency of hydroxyvitamin D derivatives in inhibiting TGF-β1-induced collagen and hyaluronan synthesis and inhibiting cell proliferation. The in vivo activity of 20(OH)D(3) was tested using bleomycin-induced sclerosis in C57BL/6 mice.

RESULTS

20(OH)D(3) and 20,23(OH)(2)D(3) inhibited TGF-β1-induced collagen and hyaluronan synthesis similarly to 1,25(OH)(2)D(3) in cultured human fibroblasts. Also, 20(OH)D(3), 20,23(OH)(2)D(3), and 1,25(OH)(2)D(3) suppressed TGF-β1-induced expression of COL1A2, COL3A1, and hyaluronan synthase-2 mRNA, indicating that they regulate these matrix components at the transcriptional level. 20(OH)D(3), 20,23(OH)(2)D(3), 20,22(OH)(2)D(3), and 17,20,23(OH)(3)D(3) inhibited proliferation of dermal fibroblasts with comparable potency with 1,25(OH)(2)D(3), with 20(OH)D(2) being less active and 1α(OH)D(3) being almost inactive. 20,23(OH)(2)D(3) at 3 μg/kg had no effect on serum Ca(++) or fibroblast growth factor-23 levels and did not cause any noticeable signs of morbidity. 20(OH)D(3) markedly suppressed fibrogenesis in mice given sc bleomycin as demonstrated by total collagen content and hematoxylin and eosin staining of skin biopsies.

CONCLUSIONS

20(OH)D(3) is an excellent candidate for preclinical studies on scleroderma, with other CYP11A1-derived products of its metabolism deserving further testing for antibrogenic activity.

Identification of specific chondroitin sulfate species in cutaneous autoimmune disease

Cutaneous lupus erythematosus and dermatomyositis (DM) are chronic inflammatory diseases of the skin with accumulated dermal mucin. Earlier work has shown chondroitin sulfate (CS) accumulation within the dermis of discoid lupus erythematosus (DLE), subacute cutaneous lupus erythematosus (SCLE), and DM lesions compared with control skin. Immunohistochemistry for C4S revealed a greater density in DLE and DM lesions, whereas SCLE lesions did not differ from controls. Scleredema and scleromyxedema are attributed to increased hyaluronic acid, and lesional samples from these diseases also demonstrated accumulated dermal C4S. Interferon-γ and interleukin-1α, but not interferon-α, treatment of cultured dermal fibroblasts induced mRNA expression of CHST-11, which attaches sulfates to the 4-position of unsulfated chondroitin. These studies on possible CS core proteins revealed that serglycin, known to have C6S side chains in endothelial cells, had greater density within DM dermal endothelia but not in DLE or SCLE, following the pattern of C6S overexpression reported previously. CD44 variants expand the CS binding repertoire of the glycoprotein; CD44v7 co-localized to the distribution of C4S in DLE lesions, a finding not observed in DM, SCLE lesions, or controls. Because C4S and C6S have immunologic effects, their dysregulation in cutaneous mucinoses may contribute to the pathogenesis of these disorders.

Inflammatory alterations of the extracellular matrix in the tumor microenvironment

Complex interactions between cancer cells and host stromal cells result in the formation of the "tumor microenvironment", where inflammatory alterations involve the infiltration of tumor-associated fibroblasts and inflammatory leukocytes that contribute to the acquisition of malignant characteristics, such as increased cancer cell proliferation, invasiveness, metastasis, angiogenesis, and avoidance of adaptive immunity. The microenvironment of a solid tumor is comprised not only of cellular compartments, but also of bioactive substances, including cytokines, growth factors, and extracellular matrix (ECM). ECM can act as a scaffold for cell migration, a reservoir for cytokines and growth factors, and a signal through receptor binding. During inflammation, ECM components and their degraded fragments act directly and indirectly as inflammatory stimuli in certain cases and regulate the functions of inflammatory and immune cells. One such ECM component, hyaluronan, has recently been implicated to modulate innate immune cell function through pattern recognition toll-like receptors and accelerate the recruitment and activation of tumor-associated macrophages in inflamed cancers. Here, we will summarize the molecular mechanism linking inflammation with ECM remodeling in the tumor microenvironment, with a particular emphasis on the role of hyaluronan in controlling the inflammatory response.

Stimulation of epidermal calcium gradient loss increases the expression of hyaluronan and CD44 in mouse skin

BACKGROUND

Hyaluronan (HA), a major extracellular matrix component in epidermis, has been found to accumulate in the epidermis after disruption of the epidermal barrier; however, the precise mechanisms underlying this process are not yet clear. Alterations in the epidermal calcium gradient are an important signal for permeability-barrier homeostasis. Thus, we hypothesized that epidermal calcium-ions might regulate HA expression.

AIM

To investigate whether changes in the epidermal calcium gradient and subsequent induction of cytokines regulate HA, HA synthase (HAS) and HA receptor (CD44) expression in mouse epidermis, and to clarify the mechanisms of HA induction.

METHODS

Sonophoresis of 1.5 mmol/L Ca(2+)-containing gel or Ca(2+)-free gel was performed to manipulate the epidermal Ca(2+) content without disrupting the permeability barrier. We also manipulated the Ca(2+) gradient by tape-stripping with or without 2 h immersion in 1.2 mmol/L Ca(2+)-containing solutions. Next we inhibited cytokine activity using tumour necrosis factor (TNF)-alpha or interleukin (IL)-1 inhibitors before sonophoresis. Six hours after each treatment, the expression of HA, HAS and CD44 were analysed using reverse transcription PCR and immunohistochemical stains.

RESULTS

Sonophoresis of Ca(2+)-free gel significantly increased HA, HAS3 and CD44 expression in epidermis and in tape-stripped skin. However, the inhibition of Ca(2+) decrease in the upper epidermis by sonophoresis of Ca(2+)-containing gel or immersion of barrier-disrupted skin into a Ca(2+)-containing solution attenuated these inductions. Specific inhibitors of TNF-alpha and IL-1 specific inhibitors also abolished the sonophoresis-induced expression of HA, HAS3 and CD44.

CONCLUSIONS

These results suggest that modulations in epidermal calcium regulate HA and CD44 expression directly or via induction of cytokines.

Dermatomyositis

Dermatomyositis (DM) is a chronic inflammatory disorder of the skin and muscles. Although thought to be autoimmune in origin, many questions remain as to the etiopathogenesis of this disease. DM has classically been considered a humorally mediated disease. Current evidence, however, seems to increasingly support alternative (though not mutually exclusive) mechanisms of pathogenesis, including cell-mediated and innate immune system dysfunction. Pathologic findings of DM in muscle include infarcts, perifascicular atrophy, endothelial cell swelling and necrosis, vessel wall membrane attack complex deposition, and myocyte-specific MHC I upregulation. As for the skin, histopathologic findings include hyperkeratosis, epidermal basal cell vacuolar degeneration and apoptosis, increased dermal mucin deposition, and a cell-poor interface dermatitis. Autoantibodies, particularly those that bind nuclear or cytoplasmic ribonucleoprotein antigens, are also commonly found in DM, although their importance in pathogenesis remains unclear. Defective cellular clearance, genetic predilection and environmental exposures, such as viral infection, may also play an important role in the pathogenesis of DM. The seminal work regarding the pathogenesis of DM is reviewed and an update on the recent basic and molecular advances in the field is provided.

Involvement of hyaluronan in regulation of fibroblast phenotype

This study aimed to understand the role of the matrix polysaccharide, hyaluronan (HA), in influencing the scarring process by assessing its impact on regulating fibroblast behavior. Donor-matched human oral and dermal fibroblasts were used as models of nonscarring and scarring fibroblast phenotypes, respectively. Phenotypic differences in these two fibroblast populations were assessed and related to differences in HA synthesis and assembly. The two fibroblast populations showed intrinsic differences in their response to the profibrotic cytokine, transforming growth factor-beta1 (TGFbeta1), in that oral fibroblasts were resistant to TGFbeta1-driven myofibroblastic differentiation. In dermal fibroblasts, differentiation was associated with an induction of HA synthase (HAS1 and HAS2) transcription and assembly of pericellular HA coats. In comparison, resistance to differentiation in oral fibroblasts was associated with failure of induction of HAS1 and HAS2 transcription and failure of pericellular coat assembly. Furthermore, inhibition of HA synthesis in dermal fibroblasts significantly attenuated TGFbeta1-mediated differentiation. Interleukin-1beta stimulation resulted in induction of HAS1 and HAS2 transcription but did not induce phenotypic differentiation or induce HA coat assembly. In addition, neither overexpression nor down-regulation of HAS1 (the isoform uniquely deficient in nonscarring oral fibroblasts) influenced phenotypic differentiation. In conclusion, inhibiting HA synthesis modulates TGFbeta1-dependent responses in these cells preventing fibroblast to myofibroblast differentiation. Moreover, HA pericellular coat assembly, rather than HAS isoform expression, appears to be associated with phenotypic differentiation.

Regulation of hyaluronan synthase-2 expression in human intestinal mesenchymal cells: mechanisms of interleukin-1beta-mediated induction

Elevated levels of hyaluronan are associated with numerous inflammatory diseases including inflammatory bowel disease. The purpose of this study was to determine whether a cause and effect relationship might exist among proinflammatory cytokines, IL-1beta, TNF-alpha, IFN-gamma, or transforming growth factor-beta (TGF-beta) and hyaluronan expression in human JDMC and, if so, to identify possible mechanisms involved in the induction of hyaluronan expression. TGF-beta, TNF-alpha, and IFN-gamma had little or no effect on hyaluronan production by these cells. Treatment with IL-1beta induced an approximate 30-fold increase in the levels of hyaluronan in the medium of human jejunum-derived mesenchymal cells. Ribonuclease protection analysis revealed that steady-state transcript levels for hyaluronan synthase (HAS)2 were present at very low levels in untreated cells but increased as much as 18-fold in the presence of IL-1beta. HAS3 transcript levels were also increased slightly by exposure of these cells to IL-1beta. Expression of HAS1 transcripts was not detected under any condition in these cells. IL-1beta induction of hyaluronan expression was inhibited in cells transfected with short interfering RNA corresponding to HAS2 transcripts. Inhibitors of the p38 and ERK1/2 mitogen-activated pathways but not JNK/SAPK blocked the IL-1beta-mediated induction of hyaluronan expression and the increase in HAS2 transcript expression. These results suggest that IL-1beta induction of HAS2 expression involves multiple signaling pathways that act in concert, thus leading to an increase in expression of hyaluronan by jejunum-derived mesenchymal cells.

Serum hyaluronan and hyaluronidase: very early markers of toxic liver injury

BACKGROUND

Dimethylnitrosamine (DMN), a potent hepatotoxin, administered to rats, provides a convenient model for toxic liver injury. Indicators of early liver injury are important clinically, for surveillance, for screening new drugs that are potentially hepatotoxic and for identifying drugs that protect against liver injury. Both cirrhosis and wound healing culminate in deposition of fibrous connective tissue and scarring. Increased hyaluronan (HA) occurs in the earliest stage of wound healing. Hyaluronidase, the enzyme that degrades hyaluronan, is also elevated whenever rapid turnover of hyaluronan occurs. We test the hypothesis that elevated levels of circulating hyaluronan and hyaluronidase could provide indicators of very early liver damage.

METHODS

Dimethylnitrosamine was administered to adult male albino rats by intraperitoneal injections for 7 consecutive days.

RESULTS

Increased serum hyaluronan levels observed on day 2 reached a maximum on day 4. Hyaluronidase was elevated on the first day and reached a maximum on day 2 that was 30-times control levels. Hyaluronan-specific staining in liver sections was maximal on day 7, occurring predominantly in portal triads and in sinusoidal spaces. Individual hepatocytes were slightly enlarged and contained intracellular hyaluronan, which was not evident in control sections. Though circulating hyaluronan levels had decreased after day 4, continued hyaluronan staining persisted in liver sections through day 21. Conventional indicators of liver injury, such as serum aminotransferase enzymes, did not reach a peak until day 7. Conventional gross and histopathological changes, including severe centrilobular congestion and hemorrhagic necrosis, were observed only after day 7. Both hyaluronan and hyaluronidase are indicators of very early liver damage in the dimethylnitrosamine-treated rat, occurring well before conventional indicators appear, or before overt histopathologic changes of liver damage can be seen. However, levels are increased only transiently, indicating that serial assays are necessary.

CONCLUSIONS

Measures of circulating hyaluronidase activity may be used to assess liver damage.

Hyaluronan facilitates invasion of colon carcinoma cells in vitro via interaction with CD44

Hyaluronan (HA) and its biosynthetic enzymes, HA synthases (HAS1, 2, and 3) are thought to participate in cancer progression. We have shown previously that HA production and HAS3 expression are increased in metastatic colon carcinoma cells (SW620) when compared with cells isolated from a primary tumor (SW480). Because invasion of the extracellular matrix is a fundamental event in tumor growth and metastasis, we hypothesized that SW620 cells would show greater invasive capability than SW480 cells, that invasion is HA dependent, and that HA mediates invasion via interaction with a cell-surface receptor. Invasion into artificial basement membrane (Matrigel) was assessed in vitro. To assess HA functionality, HAS expression was inhibited in SW620 cells by transfection with antisense HAS constructs. Decreased HA secretion and retention in the transfectants were confirmed using competitive binding and particle exclusion assays. SW620 cells demonstrated greater invasion through Matrigel than did SW480 cells. Antisense transfection decreased Matrigel invasion by SW620 cells by >60%; addition of exogenous HA restored invasion. Because the cell-surface HA receptor CD44 has been implicated in cancer progression, HA-CD44 interaction was then inhibited by incubation with an anti-CD44 antibody. Anti-CD44 antibody impaired invasion into Matrigel by 95%. Taken together, these data suggest that pericellular HA is critical for colon carcinoma cell invasion and that this invasive capability is dependent on interaction with CD44.

Hyaluronan synthase-3 is upregulated in metastatic colon carcinoma cells and manipulation of expression alters matrix retention and cellular growth

HA is a glycosaminoglycan that is synthesized on the inner surface of the plasma membrane and secreted into the pericellular matrix. HA and its biosynthetic enzymes (HAS1, HAS2 and HAS3) are thought to participate in tumor growth and cancer progression. In our study, colon carcinoma cells isolated from a lymph node metastasis (SW620) produced more pericellular HA and expressed higher levels of HAS3 mRNA compared to cells isolated from a primary colon carcinoma (SW480). To assess functionality, HAS3 expression in SW620 cells was inhibited by transfection with an asHAS3 construct. Decreased HA secretion and cell-surface retention by asHAS3 transfectants were confirmed using competitive binding and particle exclusion assays. Anchorage-independent growth, a correlate of tumor growth in vivo, was assessed by colony formation in soft agar. SW620 cells stably transfected with asHAS3 demonstrated significant growth inhibition, as evidenced by fewer colonies and smaller colony area than either SW620 cells or cells transfected with vector alone. Addition of exogenous HA restored growth in asHAS3 transfectants. Thus, we demonstrate that pericellular HA secretion and retention and HAS3 expression are increased in metastatic colon carcinoma cells relative to cells derived from a primary tumor. Inhibition of HAS3 expression in these cells decreased the pericellular HA matrix and inhibited anchorage-independent growth. These data suggest that HA and HAS3 function in the growth and progression of colon carcinoma.

Hyaluronan synthase 3 regulates hyaluronan synthesis in cultured human keratinocytes

Three human hyaluronan synthase genes (HAS1, HAS2, and HAS3) have been cloned, but the functional differences between these HAS genes remains obscure. The purpose of this study was to examine which of the HAS genes are selectively regulated in epidermis. We examined the relation of changes between hyaluronan production and HAS gene expression when cytokines were added to cultured human keratinocytes. Interferon-gamma increased hyaluronan production whereas transforming growth factor beta decreased it. Both cytokines affected preferentially high-molecular-mass (> 106 Da) hyaluronan production. Consistent with the change in hyaluronan synthesis, we found that interferon-gamma markedly upregulated HAS3 mRNA whereas transforming growth factor beta downregulated HAS3 transcript levels. The expression of HAS1 mRNA was not significantly affected by either cytokine, and HAS2 mRNA expression was undetectable under either basal or cytokine-stimulated conditions by northern blot using total RNA. Furthermore, in situ mRNA hybridization showed that mouse epidermal keratinocytes abundantly expressed HAS3 mRNA from the basal to the granular cell layers, suggesting that HAS3 functions in epidermis. These findings suggest that HAS3 gene expression plays a crucial role in the regulation of hyaluronan synthesis in the epidermis.

Dermatomyositis and mucinosis

BACKGROUND

Mucin deposition is a common feature in autoimmune collagen diseases including dermatomyositis. Nevertheless, clinical manifestations of mucinosis are uncommon in patients with dermatomyositis. Two cases of mucinosis associated with dermatomyositis are reported.

PATIENTS

A 53-year-old woman presented with symmetrical plaques on the upper limbs formed by the coalescence of small, violaceous papules. In addition, she showed the typical cutaneous and muscle features of dermatomyositis. A 44-year-old woman with dermatomyositis of 5 years' evolution developed linear, flesh-colored papules across the flexural creases of her palms and fingers.

RESULTS

Skin biopsy of the upper limb lesions in the first patient showed epidermal changes compatible with dermatomyositis and dermal mucin deposition. Histopathologic examination of the palmar lesions of the second patient showed less intense epidermal changes of dermatomyositis and dermal mucin deposition.

CONCLUSIONS

Mucin deposition in patients with dermatomyositis may have an unusual clinical presentation, and it should be considered in the differential diagnosis of atypical cutaneous lesions in these patients.

Type I and type III collagens in cutaneous mucinosis

Cutaneous mucinoses are a heterogeneous group of diseases characterized by the focal or diffuse dermal deposition of glycosaminoglycans. The histopathologic examination of many cutaneous mucinoses reveals that the collagen fibers are fragmented. We wanted to characterize the type I (COL1) and type III (COL3) collagen distribution in skin biopsy specimens of patients with cutaneous mucinosis. The diagnosis of mucinosis was based on a modification of the classification by Rongioletti and Rebora: four patients had familial papulonodular mucinosis: four had papular mucinosis, one of which was associated with myxedema and one had scleromyxedema; and one had focal mucinosis. We performed anti-type I and type III collagens immunolabeling on frozen sections. Immunofluorescence for COL1 was increased in the superficial dermis of 2/4 familial papulonodular mucinosis, in 5/5 of papular mucinosis, and in scleromyxedema and focal mucinosis cases. The mid-dermis showed intense staining for COL1 at the periphery of collagen bundles and, in three cases of familial papulonodular mucinosis and two cases of papular mucinosis, a lacy appearance. The superficial dermis of familial papulonodular mucinosis specimens and of papular mucinosis + myxedema, scleromyxedema, and focal mucinosis specimens had decreased COL3 staining. The mid-dermis showed a more prominent fibrillar staining at the periphery of the collagen bundles, and two cases of papular mucinosis showed intense labeling for COL3. Both COL1 and COL3 distributions are altered in cutaneous mucinosis. An intense labeling with COL1 is predominantly found in the superficial layer of cutaneous mucinosis. Cases of FTP revealed decreased COL3 reactivity at the superficial layer.

Hyaluronic acid-specific regulation of cytokines by human uterine fibroblasts

The physiological inflammatory response can provide an effective mechanism for delivering the baby at the time of parturition. We characterized the mechanisms by which hyaluronic acid (HA) regulates interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and interleukin-8 (IL-8) production in human uterine fibroblasts. A dose-dependent increase in cytokine release was observed over an HA concentration range of 10 microg/ml to 1 mg/ml. The action of HA on the cytokine production is mediated by CD44. Under serum-free conditions, HA-induced cytokine generation was significantly less compared with production in the presence of serum, suggesting involvement of serum proteins. Addition of inter-alpha-trypsin inhibitor (ITI) under serum-free conditions enhanced the HA-induced synthesis of TNF-alpha, which stimulated the temporary release of IL-8. In addition, HA and IL-1beta stimulated the release of hyaluronidase by the fibroblasts. These results indicate that cytokine production in human uterine fibroblasts is regulated in a CD44-HA-ITI-specific fashion. HA may be involved in the regulation of delivery in part through the selective release of cytokines that contribute to uterine cervical ripening.

TSG-6: an IL-1/TNF-inducible protein with anti-inflammatory activity

The pro-inflammatory cytokines IL-1 and TNF-alpha are primary mediators of the acute phase response, the complex reaction of the mammalian organism to infection and injury. Among the genes activated by TNF-alpha and IL-1 in a variety of cells is TNF-stimulated gene 6 (TSG-6). The TSG-6 cDNA encodes a secreted 35 kDa glycoprotein which is abundant in synovial fluids of patients with various forms of arthritis and detectable in serum of patients with different inflammatory or autoimmune disorders. TSG-6 protein consists of two structural domains: a hyaluronan-binding link module, the characteristic domain of the hyaladherin family of proteins, and a C-terminal CUB domain, present in a variety of diverse proteins. TSG-6 forms a stable complex with components of the plasma protein inter-alpha-inhibitor (I[alpha]I), a Kunitz-type serine protease inhibitor. TSG-6 and I(alpha)I synergize to inhibit plasmin, a serine protease involved in the activation of matrix metalloproteinases which are part of the proteolytic cascade associated with inflammation. Recombinant human TSG-6 protein exerts a potent anti-inflammatory effect in a murine model of acute inflammation. Modulation of the proteolytic network associated with inflammatory processes may be a mechanism whereby TSG-6, in cooperation with I(alpha)I, inhibits inflammation. Activation of the TSG-6 gene by pro-inflammatory cytokines, presence of TSG-6 protein in inflammatory lesions and its anti-inflammatory effect suggest a role for TSG-6 in a negative feed-back control of the inflammatory response.

Differential response of fetal and adult fibroblasts to cytokines: cell migration and hyaluronan synthesis

Previous studies have indicated that fetal skin fibroblasts display an elevated level of migratory activity compared to adult cells and that this may result from inherent differences in the production of hyaluronan (HA) by these cells. Data presented in this communication indicate that the elevated level of fetal fibroblast migration into 3D-collagen gels and HA synthesis by these cells were not affected by epidermal growth factor (EGF), platelet-derived growth factor (PDGF), acidic fibroblast growth factor (aFGF) or basic fibroblast growth factor (bFGF). In contrast, both cell migration and HA synthesis by fetal fibroblasts were inhibited by transforming growth factor-betal (TGF-beta1). Adult fibroblasts responded to these cytokines in a distinct fashion: i.e. cell migration and HA synthesis were stimulated by EGF, PDGF, aFGF and bFGF, but remained unaffected by TGF-beta1. Gel-filtration chromatography revealed that these effects of cytokines on HA synthesis were predominantly confined to the production of high molecular mass (>106 kDa) species. Co-exposure of cells to both cytokines and Streptomyces hyaluronidase revealed that (1) the elevated migration of control fetal fibroblasts was inhibited by hyaluronidase, (2) this inhibition was partially restored by co-exposure to EGF, PDGF, aFGF and bFGF, but remained unaffected by TGF-beta1, (3) the migration of control adult fibroblasts was unaffected by hyaluronidase and partially stimulated by EGF, aFGF and bFGF (when compared to the effects of these cytokines on cells cultured in the absence of hyaluronidase) and (4) neither PDGF nor TGF-beta1 affected the migration of hyaluronidase-treated adult cells. Linear regression analysis revealed a significant correlation between cell migration and HA synthesis by both fetal and adult fibroblasts in the presence and absence of cytokines (r2=0.9277, P<0.0001), with the exception of adult fibroblasts exposed to PDGF. Taken together, these findings suggest that (1) the migration of fetal and adult fibroblasts is differentially modulated by exogenous cytokines and (2) with the possible exception of the effects of PDGF on adult fibroblasts, cytokine-induced modulation of cell migration appears to utilise both HA-dependent and HA-independent pathways.

Adhesion molecules involved in the binding of murine myeloma cells to bone marrow stromal elements

In previous work, we reported the development of the B9/BMI syngeneic murine bone marrow metastasis model. Interleukin (IL)-6-dependent, IL-I-producing B9/BMI cells, which preferentially home to and colonise the vertebral and femoral marrow after i.v. injection, exhibit striking similarity in cell surface phenotype to human myeloma cells, especially the expression of 3 adhesion molecules, CD44, VLA-4 and ICAM-I. Because the haematopoietic microenvironment consists of different cell types, such as endothelial cells, fibroblasts, adipocytes and macrophages, we investigated the functional significance of these adhesion molecules in heterotypic binding assays between B9/BMI cells and a newly established bone marrow-derived endothelial cell line (BMEC), a fibroblastoid pre-adipocyte cell line (BMS2.2) and primary bone marrow-derived macrophages. B9/BMI cells adhered well to all stromal elements: a combination of monoclonal antibodies (MAbs) against CD44 and VLA-4 significantly inhibited the adherence of B9/BMI cells to BMEC and BMS2.2 cells, whereas binding of B9/BMI cells to macrophages was partially blocked with an anti-ICAM-I MAb. Our results implicate multiple recognition mechanisms, including those involving CD44, VLA-4 and ICAM-I, in the retention of B9/BMI cells in the bone marrow.

Reticular erythematous mucinosis syndrome associated with psoriasis-like eruptions

We report a case of reticular erythematous mucinosis syndrome associated with psoriasis-like eruptions. Although the two skin diseases are clinically distinct, they may be related in some ways.

Leukoregulin induces plasminogen activator inhibitor type 1 in human orbital fibroblasts

Leukoregulin, a 50-kDa T lymphocyte-derived cytokine, influences the synthesis of collagenase, stromelysin-1, collagen, and hyaluronan in human fibroblasts and is thus a determinant of extracellular matrix economy. We studied the effect of leukoregulin on the expression of plasminogen activator inhibitor type 1 (PAI-1) in human orbital and dermal fibroblasts. The lymphokine upregulated 35S-labeled PAI-1 protein expression in orbital fibroblasts in dose-dependent manner. The effect on extracellular matrix-associated PAI-1 evolved over several hours and was maximal at 10 h, when levels were 75-fold higher than controls, and then fell by 24 h. Leukoregulin treatment increased prostaglandin E2 production in orbital cultures after 24 h. When this increase was blocked with indomethacin, peak PAI-1 levels were maintained. Northern analysis demonstrated a substantial induction of steady-state PAI-1 mRNA levels within 6 h of treatment in orbital cultures. In contrast, leukoregulin lowered PAI-1 protein levels dramatically in skin fibroblasts from the abdominal wall. With regard to PAI-1 expression, it would appear that the anatomic site of origin of fibroblasts is a crucial determinant of the cellular response to leukoregulin.

Increased hyaluronan production in the glomeruli from diabetic rats: a link between glucose-induced prostaglandin production and reduced sulphated proteoglycan

Exposure in vivo or in vitro to elevated glucose increases production of vasoactive prostaglandins by glomeruli and mesangial cells. This study aimed to determine whether this increased prostaglandin production could provide a link with later structural changes in diabetic nephropathy. Glomerular cores were prepared from control rats and streptozotocin-diabetic rats (3 weeks' duration). Over 24 h in culture hyaluronan production from diabetic glomerular cores was higher than production from control glomerular cores whether maintained in 5.6 mmol/l glucose (105.6 +/- 15.5 vs 53.6 +/- 8.5 ng hyaluronan per 250 glomerular cores, p < 0.001); in 25 mmol/l glucose (149.3 +/- 34.8 vs 62.7 +/- 7.8 ng hyaluronan per 250 glomerular cores, p < 0.01); or in 45 mmol/l glucose (176.8 +/- 23.3 vs 102.0 +/- 17.9 ng hyaluronan per 250 glomerular cores, p < 0.01). At 5.6 mmol/l glucose, exposure in vitro to prostaglandin E2 caused an increase in hyaluronan production [maximal at 10(-9) mol/l prostaglandin E2, 237 +/- 19 vs 42 +/- 4, ng hyaluronan per 250 glomerular cores, p < 0.001 (control) and 195 +/- 7 vs 103 +/- 5, ng hyaluronan per 250 glomerular cores, p < 0.001 (diabetic)]. In both control and diabetic glomerular cores hyaluronan production was reduced significantly by the cyclooxygenase inhibitor indomethacin (10(-5) mol/l) [24.7 +/- 3.33 vs. 40.25 +/- 4.11 ng hyaluronan per 250 glomerular cores, p < 0.05 (control) and 36.5 +/- 6.25 vs 118.0 +/- 22.6, p < 0.01 (diabetic)]. A direct spectrophotometric microassay was used to determine the concentration of sulphated glycosaminoglycans derived from papain-digested glomerular core proteoglycans.(ABSTRACT TRUNCATED AT 250 WORDS)

Papulonodular mucinosis associated with systemic lupus erythematosus: possible mechanisms of increased glycosaminoglycan accumulation

BACKGROUND

The mechanism for the production of papulonodular mucinosis in patients with lupus erythematosus (LE) is not known.

OBJECTIVE

Our purpose was to determine whether fibroblasts in a patient with LE and papulonodular mucinosis produced more mucin than normal fibroblasts and whether this mucin production could be stimulated by the patient's serum.

METHODS

Skin fibroblasts from a patient with systemic LE and massive papulonodular mucin deposition, as well as normal fibroblasts, were incubated in the presence of serum from the patient or from a healthy volunteer. The production of glycosaminoglycan by fibroblasts was analyzed.

RESULTS

Fibroblasts from the patient produced more glycosaminoglycan than did normal fibroblasts. Glycosaminoglycan production was increased in all cells when incubated in the presence of the patient's serum.

CONCLUSION

Cutaneous mucin deposition in patients with papulonodular LE skin lesions is associated with increased glycosaminoglycan production by dermal fibroblasts. Our preliminary observations suggest glycosaminoglycan production by these fibroblasts appears to be stimulated by a factor, (or factors) in the patient's serum that is yet to be identified.

Role of T cells and cytokines in effecting fibrosis

A number of humoral and cellular immune abnormalities are present in patients with early scleroderma (systemic sclerosis). Most of these abnormalities reflect ongoing autoimmune reactions of the cellular and humoral types, resulting in a variety of autoantibodies to cellular and tissue constituents. Evidence exists for a defect(s) in immunoregulation favoring excessive helper T cell activity. The presence of circulating cytokines and shed interleukin-2 receptors suggest ongoing cellular immune reactions are occurring, generating cytokines and lymphokines that are capable of effecting the vascular and fibrotic lesions that are hallmarks of the disease. Future directions for research are suggested that would focus on determining if, and at what point, fibroblasts might function autonomously to generate excessive matrix components and on determining the nature of the original antigenic stimulus that starts the scleroderma process.

The interdependent modulation of hyaluronan synthesis by TGF-beta 1 and extracellular matrix: consequences for the control of cell migration

The principal objective of this communication has been to determine the manner in which two tissue culture substrata (plastic dishes and type I collagen gels) modulate the response of adult skin fibroblasts to TGF-beta 1 with respect to hyaluronan (HA) synthesis. Our results indicate that (a) fibroblasts cultured on collagen gels synthesised more HA compared to cells plated at the same density on plastic dishes, (b) this up-regulation in total HA synthesis by collagen-cultured cells was accompanied by an increase in the relative proportion of high molecular mass species of newly synthesised HA, and (c) the specific effect of TGF-beta 1 on HA synthesis was dependent upon the substratum: i.e. TGF-beta 1 inhibited HA synthesis by subconfluent fibroblasts cultured on both substrata, had no apparent effect on confluent cells cultured on collagen gels, and stimulated HA synthesis by confluent cells cultured on plastic dishes. The TGF beta-stimulated of HA synthesis by confluent fibroblasts cultured on plastic dishes persisted when these cells were transferred to collagen gels in the absence of further TGF-beta 1: interestingly, a second exposure of these plastic pre-incubated cells to TGF-beta 1 whilst growing on collagen resulted in a down-regulation in HA synthesis. Confluent fibroblasts pre-incubated with TGF-beta 1 for 24 h on plastic dishes (i.e. under conditions which stimulate HA synthesis) also displayed an HA-dependent stimulation in cell migration when subsequently plated onto collagen gels in the absence of further cytokine.

Osteogenic protein-1, a bone morphogenic protein member of the TGF-beta superfamily, shares chemotactic but not fibrogenic properties with TGF-beta

We have previously shown that recombinant human osteogenic protein-1 (rhOP-1), a bone morphogenetic protein member of the TGF-beta superfamily, can induce new bone formation when implanted with an appropriate carrier at subcutaneous sites in rats and can restore completely large diaphyseal segmental defects in laboratory animals. The role of OP-1 in the early events of bone induction viz, chemotaxis of phagocytic leukocytes, and fibroblastic mesenchymal cells is currently unknown. In the present study, we examined the effect of rhOP-1 on chemotaxis of phagocytic leukocytes (human neutrophils and monocytes) and fibroblastic mesenchymal cells (infant foreskin fibroblasts). Since OP-1 is structurally related to TGF-beta 1, we assessed the effects of OP-1 on several other fibroblast functions (in addition to chemotaxis) known to be modulated by TGF-beta 1. Our results demonstrated that rhOP-1, like TGF-beta 1, is a potent chemoattractant for human neutrophils, monocytes, and fibroblasts. However, in contrast to TGF-beta 1, OP-1 does not to stimulate fibroblast mitogenesis, matrix synthesis [collagen and hyaluronic acid (hyaluronan)], or production of tissue inhibitor of metalloproteinase (TIMP), i.e., fibroblast functions associated with fibrogenesis. These results clearly demonstrate a dichotomy between these two members of the TGF-beta superfamily with a regard to fibrogenic effects on fibroblasts but a similarity in their chemotactic properties.

Interferon-alpha 2a increases serum concentration of hyaluronic acid and type III procollagen aminoterminal propeptide in patients with chronic hepatitis B virus infection

Interferon-alpha (IFN-alpha) has become an important drug for the treatment of chronic viral liver diseases. However, the action of IFN-alpha remains unclear. We investigated whether human recombinant IFN-alpha modulates serum concentrations of hyaluronic acid (HA) and type III procollagen aminoterminal propeptide (P-III-NP) in 56 patients with chronic hepatitis-B under IFN-alpha therapy. IFN-alpha increased the HA serum level in 44 of 46 patients and, after cessation of treatment, HA serum levels returned to the pretherapy levels. The increase of HA serum level was higher in patients with active cirrhosis (aC) than in patients with chronic persistent hepatitis (CPH) and in patients with severe inflammation compared to those with moderate inflammation. Interestingly, HA serum concentration was unrelated to IFN dose and was of no predictive value for therapy response. In contrast, IFN-alpha increased significantly the P-III-NP serum level in patients with aC only. During follow-up, P-III-NP serum level decreased late in responders in parallel to the decrease of serum level of liver enzymes, in non-responders it was without significant change. The first dose of IFN induced a significant increase in HA serum level in each of 10 patients but in none of four healthy volunteers. In contrast, P-III-NP serum concentrations were not influenced by the first IFN-alpha dose. We conclude that: (1) immunstimulation with IFN-alpha induces a rapid increase of HA serum level in patients with chronic hepatitis B but not in normal persons; (2) IFN-alpha increases P-III-NP serum level only in patients with active liver cirrhosis; (3) measurement of HA and P-III-NP serum levels does not help predict response to IFN-alpha, and (4) HA serum level may be used as a compliance indicator.

Upregulation of fibronectin synthesis by interleukin-1 beta in coronary artery smooth muscle cells is associated with the development of the post-cardiac transplant arteriopathy in piglets

We previously described in piglets after heterotopic cardiac transplantation the early development of a coronary arteriopathy characterized by increased immunostaining for fibronectin and interleukin-1 beta (IL-1 beta) in the vessel wall. The objective of this study was to culture smooth muscle cells from donor and host coronary arteries in these piglets to determine whether donor cells produce more fibronectin than host cells as judged by increased protein and mRNA levels, and whether IL-1 beta may be regulating this increase by an autocrine mechanism involving increased production of the cytokine. We documented increased donor coronary artery smooth muscle cell fibronectin protein synthesis and mRNA compared to host. By using neutralizing antibodies to IL-1 beta, fibronectin protein synthesis and mRNA levels were reduced in donor cells to the levels observed in the host cells and a similar reduction in synthesis was observed with the IL-1 receptor antagonist. Immunoprecipitation of newly synthesized IL-1 beta revealed increased endogenous levels in donor compared to host cells. We therefore suggest in the coronary arteriopathy a pathophysiologic mechanism whereby IL-1 beta-mediated increased fibronectin synthesis may promote lymphocyte trapping and migration of medial smooth muscle cells leading to progressive intimal thickening associated with the post-cardiac transplant coronary arteriopathy.

Interleukin-1 beta regulation of fibroblast proteoglycan synthesis involves a decrease in versican steady-state mRNA levels

This study investigates the effects of interleukin (IL)-1 beta on proteoglycan metabolism by fibroblasts surrounded by endogenous extracellular matrix. In both three-dimensional matrix cultures and long-term monolayer cultures IL-1 beta caused a significant decrease in synthesis and deposition of sulphated proteoglycans, but had no effect on release of deposited material. The decrease in synthesis became successively more pronounced, and corresponded to 40-60% of the control after 72 h incubation. The reduction was almost totally accounted for by an effect on the chondroitin ABC-lyase-sensitive proteoglycans. Gel electrophoresis showed a significant decrease in a high-molecular-mass chondroitin ABC-lyase-sensitive proteoglycan after incubation with IL-1 beta. Northern-blot analyses of total RNA revealed a pronounced decrease in the steady-state mRNA levels of versican, the large chondroitin sulphate, with levels corresponding to 10-30% of controls. In comparison, the steady-state mRNA level for decorin, the major sulphated proteoglycan synthesized by the cells, was only slightly affected. The prominent decrease in synthesis of sulphated proteoglycans induced in long-term fibroblast cultures, including the pronounced decrease in versican steady-state mRNA levels, is likely to have a significant effect on the structure of the extracellular matrix. Induction of this type of change may constitute a significant mechanism whereby IL-1 beta can affect the properties of connective tissue during inflammation and wound healing.

Regulation of hyaluronate production by interleukin 1 in cultured human chorionic cells

Human chorionic cells in culture synthesized and secreted a large amount of hyaluronate as well as tissue collagenase. When these cells were treated with human recombinant interleukin 1 alpha (hrIL-1), the biosynthesis and secretion of hyaluronate were predominantly accelerated, but those of sulfated glycosaminoglycans were not modulated. This promotive effect of hrIL-1 was not due to the increase in endogenous prostaglandins including prostaglandin E2 since cyclooxygenase inhibitors, indomethacin and diclofenac did not modulate the IL-1-mediated production of hyaluronate. On the other hand, the cotreatment of chorionic cells with hrIL-1 and cycloheximide suppressed the IL-1-mediated hyaluronate production, suggesting that protein, de novo, synthesis required for the enhancement of hyaluronate synthesis. Upon treatment with hrIL-1, the membrane bound-hyaluronate synthase activity was increased up to 5-fold in a time-dependent manner. On the other hand, when chorionic cells were treated with hrIL-1 and/or protein kinase C inhibitor, 1-(5-isoquinolinesulfonyl)-2-methyl-pyperadine hydrochloride (H7), the IL-1-mediated production of hyaluronate was effectively suppressed. Similarly, H7 effectively suppressed the protein kinase activator, 12-O-tetradecanoyl-phorbol-13-acetate-enhanced production of glycosaminoglycans with a similar extent. These results indicate that IL-1-induced acceleration of hyaluronate production was reflected on the increase in hyaluronate synthase activity, and that protein kinase C participates positively in the IL-1-signal transduction for the increased synthesis of hyaluronate in human chorionic cells.

Prostaglandin E2 stimulates cyclic AMP-mediated hyaluronan synthesis in rabbit pericardial mesothelial cells

We studied the effects of prostaglandin E2 (PGE2) on hyaluronan synthesis in rabbit pericardial mesothelial cells, and the following results were obtained. (1) PGE2 (10-1000 ng/ml) stimulated hyaluronan synthesis and the level of hyaluronan synthase activity in a dose- and time-dependent manner, but PGF2 alpha did not. (2) Cyclic AMP (cAMP) levels in the cells peaked (about a 7-fold increase) at 5-10 min after adding PGE2 (1000 ng/ml). (3) Increased hyaluronan synthesis induced by PGE2 was significantly inhibited after pretreatment with either an adenylate cyclase inhibitor (2',5'-dideoxyadenosine) or a cAMP-dependent protein kinase inhibitor (PKI 5-24), but there was no inhibition with the protein kinase C inhibitor H-7. (4) When the intracellular cAMP level was raised by manipulating the levels of dibutyryl cyclic AMP or forskolin, hyaluronan synthesis and the level of hyaluronan synthase activity were also stimulated. These results suggest that PGE2 produced by cells stimulates hyaluronan synthesis in rabbit pericardial cells and that the stimulation mechanism involves the cAMP-mediated protein kinase signal transduction process.

Hyaluronate activation of CD44 induces insulin-like growth factor-1 expression by a tumor necrosis factor-alpha-dependent mechanism in murine macrophages

Macrophages participate in inflammatory and repair processes in part through the selective release of cytokines that contribute to tissue remodeling. Extracellular matrix components generated at inflammatory sites may influence tissue remodeling by effects on leukocyte adherence and local cytokine production. In murine bone marrow-derived macrophages, we found that soluble hyaluronic acid stimulated IL-1 beta, TNF alpha, and insulin-like growth factor-1 (IGF-1) mRNA transcript expression as well as IGF-1 protein synthesis. Monoclonal antibodies to the hyaluronic acid receptor CD44 blocked the effects of hyaluronic acid on IL-1 beta, TNF alpha, and IGF-1 expression. TNF alpha and IL-1 beta mRNA expression preceded IGF-1 protein synthesis, and TNF alpha, but not IL-1 beta, was found to directly stimulate IGF-1. Furthermore, IGF-1 induction was dependent on endogenous TNF alpha production since IGF-1 protein synthesis was inhibited in the presence of anti-TNF alpha antiserum. In addition, IL-1 beta was found to exert a regulatory role on IGF-1 production by enhancing the TNF alpha effect. IL-1 beta and TNF alpha mRNA transcript expression as well as IGF-1 protein synthesis were also stimulated by chrysotile asbestos. Anti-CD44 antibodies had no effect whereas anti-TNF alpha antiserum blocked asbestos-stimulated IGF-1 production. These results indicate that hyaluronate activation of CD44 induces cytokine expression and macrophage-derived IGF-1 production is dependent on TNF alpha expression.

Interferon-gamma stimulates the secretion of IL-1, but not of IL-6, by glomerular mesangial cells

IL-1 activity in culture supernatant and cell lysate from rat mesangial cells stimulated with interferon-gamma (IFN-gamma) was measured by a thymocyte proliferation assay. While IFN-gamma alone had no effect on the secretion or the intracellular pool of IL-1, the enhancement by IFN-gamma of IL-1 secretion in response to lipopolysaccharide (LPS) was observed. The stimulatory effect of culture supernatant on thymocyte proliferation was abrogated by preincubation with the anti-IL-1 antibody. At least 4-h incubation with IFN-gamma and LPS was required to detect enhancing effect of IFN-gamma. The addition of as little as 1 U/ml IFN-gamma significantly increased IL-1 secretion in the presence of 10 micrograms/ml LPS. The IL-6 activity in culture supernatants was determined by measurement of thymidine uptake in mouse IL-6-dependent cell line (MH60.BSF2). Mesangial cells secreted IL-6 in culture supernatant without additional stimuli and LPS distinctly increased it as described previously. However, in contrast to IL-1 production, no effect of IFN-gamma on IL-6 secretion was observed in the presence or absence of LPS. Moreover, we determined whether enhanced IL-1 release is associated with Ia expression on mesangial cells. IFN-gamma alone and the combination with LPS induced marked expression of Ia antigen, whereas LPS alone did not. We conclude that IFN-gamma stimulates the production of IL-1, but not IL-6, by mesangial cells and suggest an important role of IFN-gamma in the pathogenesis of glomerulonephritis by regulating the mesangial production of IL-1 and the accessory cell function of mesangial cells.

Cytochemical localization of hyaluronan in rat and human skin mast cell granules

Rat and human skin were processed either by osmium tetroxide/microwave fixation followed by embedding in epoxy resin or by glutaraldehyde/microwave fixation and low-temperature embedding in Lowicryl K4M. Hyaluronan-binding proteins and link proteins (LP) were isolated from bovine nasal cartilage, coupled to 15-20-nm gold particles and employed as markers in a one-step post-embedding procedure for identifying hyaluronan (hyaluronic acid) at the ultrastructural level. Mast cell granules of both species were labeled. The specificity of the hyaluronan-binding probes was demonstrated by treatment of sections with testicular hyaluronidase, Streptomyces hyaluronidase, and chondroitinase ABC, and pre-incubation of probes with hyaluronan oligosaccharides. The results suggest that mast cell granules are a rich source of hyaluronan; this finding may account for the striking concurrence of hyaluronan accumulation with a mastocytotic condition in many tissues undergoing pathologic changes.

Cytokine regulation of human lung fibroblast hyaluronan (hyaluronic acid) production. Evidence for cytokine-regulated hyaluronan (hyaluronic acid) degradation and human lung fibroblast-derived hyaluronidase

We characterized the mechanisms by which recombinant (r) tumor necrosis factor (TNF), IFN-gamma, and IL-1, alone and in combination, regulate human lung fibroblast hyaluronic acid (HA) production. Each cytokine stimulated fibroblast HA production. The combination of rTNF and rIFN-gamma resulted in a synergistic increase in the production of high molecular weight HA. This was due to a synergistic increase in hyaluronate synthetase activity and a simultaneous decrease in HA degradation. In contrast, when rTNF and rIL-1 were combined, an additive increase in low molecular weight HA was noted. This was due to a synergistic increase in hyaluronate synthetase activity and a simultaneous increase in HA degradation. Human lung fibroblasts contained a hyaluronidase that, at pH 3.7, depolymerized high molecular weight HA to 10-40 kD end products of digestion. However, hyaluronidase activity did not correlate with fibroblast HA degradation. Instead, HA degradation correlated with fibroblast-HA binding, which was increased by rIL-1 plus rTNF and decreased by rIFN-gamma plus rTNF. Recombinant IL-1 and rTNF weakly stimulated and rIL-1 and rTNF in combination further augmented the levels of CD44 mRNA in lung fibroblasts. In contrast, rIFN-gamma did not significantly alter the levels of CD44 mRNA in unstimulated or rTNF stimulated cells. These studies demonstrate that rIL-1, rTNF, and rIFN-gamma have complex effects on biosynthesis and degradation which alter the quantity and molecular weight of the HA produced by lung fibroblasts. They also show that fibroblast HA degradation is mediated by a previously unrecognized lysosomal-type hyaluronidase whose function may be regulated by altering fibroblast-HA binding. Lastly, they suggest that the CD44 HA receptor may be involved in this process.

Cytokines, fibrosis and the failure of glaucoma filtration surgery

Current therapies for the prevention of fibrosis after glaucoma filtering surgery can be effective but often produce unwanted side effects. An understanding of the cellular basis of the fibrotic reaction may lead to better treatments. Wound repair revolves around angiogenesis and the activation of fibroblasts by cytokines. These peptides, a number of which have been described, act together in intricately complicated networks to encourage fibroblast chemotaxis, proliferation and contractility, as well as to stimulate the production of glycosaminoglycans and collagen. Since interferons seem to inhibit many of these responses, they deserve further evaluation in the treatment of ocular fibrosis.

Cytokine-associated tissue injury and lethality in mice: a comparative study

A comparative study was performed to examine the lethal effects of several cytokines injected into mice sensitized with actinomycin D (Act-D). Consistent with published data, human tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) (0.2-5 micrograms) caused the death of the animals within 8-12 hr after injection. Human interleukin-6 (IL-6) and interleukin-8 (IL-8) (0.6-6 micrograms) known to be induced by TNF-alpha did not show any lethal effects, indicating that TNF-alpha-associated lethality is not mediated by IL-6 or IL-8. Human tumor necrosis factor-beta (TNF-beta) (also called lymphotoxin), which shares structural and functional properties with TNF-alpha, was as potent as TNF-alpha in its lethal effects. Murine interferon-gamma (IFN-gamma) (0.04-5 micrograms) was also tested and showed no lethal effects in this model. In addition, a synthetic peptide corresponding to amino acid residues 163-171 of IL-1 beta, and which has been shown to lack the inflammatory effects of IL-1 beta, also caused no lethality among Act-D sensitized mice. The pretreatment of mice with IL-6, IL-8, or IFN-gamma had no protective effects on TNF-alpha or IL-1 beta-induced lethality in contrast to the protection observed by a pretreatment with TNF-alpha/IL-1 beta themselves or with endotoxin. Histopathologic data showed that severe tissue injury in vital organs is associated with the rapid lethality among sensitized mice.

Stimulation of collagen and glycosaminoglycan production in cultured human adult dermal fibroblasts by recombinant human interleukin 6

Interleukin (IL) 6 is a pleiotropic cytokine synthesized by fibroblasts in response to many stimuli, including IL-1 beta. To evaluate the possibility that previously observed stimulation of fibroblast biosynthetic functions by IL-1 beta may be mediated by autocrine IL-6, we investigated the effect of recombinant human (rh) IL-6 on the connective tissue-related biosynthetic functions of three lines of cultured human adult dermal fibroblasts. We found that rhIL-6 mimicked some of the activities of IL-1 beta, as 24-96-h treatment of confluent fibroblast cultures with rhIL-6 caused concentration (10 to 1000 ng/ml)-dependent increases in the production of collagen and the glycosaminoglycans (GAG), hyaluronic acid and chondroitin-4/6-sulfates, but had little effect on fibronectin or total protein production. Although the effective stimulating concentrations of IL-6 were within the range (approximately 100 ng/ml) we found produced by rhIL-1 beta-treated fibroblast cultures, rhIL-1 beta at 0.2-1.0 ng/ml induced significantly greater amounts of collagen and GAG than the maximum effective concentrations of IL-6. Moreover, an anti-rhIL-6 antibody, which effectively neutralized the fibroblast-stimulating activities of rhIL-6, only fractionally blocked the fibroblast-stimulating actions of rhIL-1 beta, suggesting autocrine IL-6 only partially mediates the effects of IL-1 beta on fibroblasts. Conversely, the fibroblast-stimulating effects of rhIL-6 are unlikely due to autocrine IL-1 beta, as an anti-rhIL-1 beta antibody had only minimal inhibitory action on rhIL-6-treated fibroblast cultures. Overall these results suggest that IL-6 could function as a paracrine/autocrine regulator of dermal fibrotic repair.

Fibroblast chemotaxis induction by human recombinant interleukin-4. Identification by synthetic peptide analysis of two chemotactic domains residing in amino acid sequences 70-88 and 89-122

Interleukin-4 is a T lymphocyte- and mast cell-derived cytokine with pleiotropic properties with biological effects on a variety of target cells including B and T lymphocytes, macrophages, hematopoietic cells, mast cells, and fibroblasts. In addition to the proliferation effect of IL-4 on fibroblasts, which has been previously described, in this report the chemotactic properties of IL-4 for fibroblasts is described. Human recombinant IL-4 induced the chemotactic migration of dermal fibroblasts in vitro in modified Boyden-type chambers at concentrations between 10(-12) and 10(-11) M. The chemotactic activity of IL-4 was neutralized by anti-human recombinant IL-4 IgG antibodies. Oligopeptides representing the complete deduced amino acid sequence of human IL-4 were synthesized by the Merrifield technique and tested for their ability to induce fibroblast chemotaxis. Two peptides representing residues 70-88 and 89-122 induced fibroblast migration. Peptide 70-88 was the more potent of the two causing chemotaxis of fibroblasts at 10(-8)-10(-6) M while peptide 89-129 induced migration at 10(-7)-10(-5) M. Although the mechanism by which IL-4 and these two peptides induce fibroblast chemotaxis is unknown, each of these three compounds were able to chemotactically desensitize fibroblasts to the chemotactic effects of the other two but not to a structurally unrelated chemotactic cytokine, transforming growth factor beta-1. These studies suggest that IL-4 might function in vivo to induce the accumulation of fibroblasts at sites of tissue injury, inflammatory and immune reactions in which T lymphocytes and mast cells participate.