Overexpression of MMP-1 and MMP-3 by cultured conjunctivochalasis fibroblasts

PURPOSE

To determine whether conjunctivochalasis, denoting redundant, loose, nonedematous inferior bulbar conjunctiva, is associated with increased expression and activity of matrix metalloproteinases (MMPS) over their tissue inhibitors (TIMPs).

METHODS

Expression of transcripts and proteins of MMPs, TIMPs, and urokinase plasminogen activator (uPA) by cultured normal human conjunctival and conjunctivochalasis fibroblasts was determined by Northern hybridization, enzyme-linked immunosorbent assay (ELISA), and Western blot analysis, respectively. Gelatin and casein zymography and quantitative collagenase activity assay were performed in the serum-free conditioned media.

RESULTS

Compared with normal conjunctival fibroblasts from six subjects, conjunctivochalasis fibroblasts from eight patients showed markedly increased transcript expression of MMP-1 (5- to 32-fold) and MMP-3 (4 to 30-fold), whereas that of MMP-2, TIMP-1, TIMP-2, and uPA was similar between the two groups. Protein levels were increased in the serum-free conditioned media of conjunctivochalasis fibroblasts for MMP-1 (3.5- to 7.6-fold) and MMP-3 (2.3- to 13-fold), determined by ELISA and Western blot analysis. There was increased caseinolytic activity of MMP-3 and collagenolytic activity of MMP-1 (2.2-fold) by conjunctivochalasis fibroblasts, whereas no difference was noted between these two types of fibroblasts in the protein and gelatinolytic activity of MMP-2 or expression of TIMP-1 and TIMP-2 proteins, although that of TIMP-1 transcript was slightly higher in some conjunctivochalasis fibroblasts. No expression of MMP-9 was detected.

CONCLUSIONS

Overexpression of MMP-1 and MMP-3 mRNA by conjunctivochalasis fibroblasts is correlated with their increased protein levels and proteolytic activities. Collectively, these data help explain how conjunctivochalasis manifests excessive degradation of the conjunctival matrix and Tenon's capsule.

HPCPC separation of proteins using polyethylene glycol-potassium phosphate aqueous two-phase

High Performance Centrifugal Partition Chromatography (HPCPC) is a practical and suitable method, particularly on the preparative scale, for the separation of biomolecules such as proteins, enzymes, etc. Aqueous two-phase system is also very attractive for the isolation of biomolecules. Aqueous polymer phase system composed of polyethylene glycol 6000-potassium phosphate has been used for the countercurrent chromatographic separation of bovine serum albumin (BSA) and lysozyme using HPCPC. The separation of BSA and lysozyme under various conditions such as various flow rates, rotational speeds, pH of the solvent, and the retention of stationary phase has been studied in the present investigation. The baseline separation of BSA and lysozyme has been also observed. The results of this study demonstrate that HPCPC is useful for separation of proteins with aqueous two-phase systems.

Differential expression and regulation of TGF-beta1, TGF-beta2, TGF-beta3, TGF-betaRI, TGF-betaRII and TGF-betaRIII in cultured human corneal, limbal, and conjunctival fibroblasts

PURPOSE

We have reported that three patterns of cytokine expression are potentially involved between epithelia and fibroblasts of the human ocular surface. The TGF-beta family is a prototypical fibrogenic cytokine responsible for fibroblast activation in wound healing. We investigated how the TGF-beta family is differentially expressed and regulated in cultured human corneal, limbal and conjunctival fibroblasts.

METHODS

Human corneal (HCF), limbal (HLF) and conjunctival fibroblast (HJF) were cultured in DMEM-10% FBS until confluence and switched to serum-free DMEM-ITS for 48 h before adding 10 ng/ml of each of eight cytokines for 4 h in three separate experiments. Total RNA was isolated and subjected to Northern hybridization with GAPDH as a control. ELISA was used to determine TGF-beta1 and TGF-beta2 proteins in the media.

RESULTS

All three isoforms of TGF-beta and three types of TGF-betaR were expressed by HCF, HLF and HJF. Expression of TGF-beta1 mRNA was strongest and upregulated by the three TGF-betas in all three types of fibroblast. PDGF-BB and TGF-alpha slightly increased TGF-beta1 mRNA. TGF-betas also upregulated TGF-beta3 mRNA in HJF. TGF-betaRI mRNA was the only receptor upregulated by TGF-betas. TGF-betaRII and TGF-betaRIII mRNA were not regulated by all cytokines tested.

CONCLUSIONS

TGF-betas auto-induction is the major mechanism upregulating TGF-beta1 expression. Promotion of TGF-beta3 by the TGF-betas may have a special role in HJF. Differential expression and regulation of TGF-betas and TGF-betaRs suggest that each TGF-beta isoform may have specific functions in different ocular surface fibroblasts. No cytokine tested can downregulate TGF-beta1 and the TGF-betaRs.

Suppression of transforming growth factor-beta isoforms, TGF-beta receptor type II, and myofibroblast differentiation in cultured human corneal and limbal fibroblasts by amniotic membrane matrix

Down-regulation of the transforming growth factor-beta (TGF-beta) signaling system is a strategy for preventing scarring during wound healing. Human corneal and limbal fibroblasts were cultured on the stromal matrix side of preserved human amniotic membrane. The levels of TGF-beta1, beta2, and beta3 and TGF-beta type II receptor transcripts and TGF-beta1 and beta2 proteins were suppressed as early as 8 hr and more dramatically at 24 hr after contact with an amniotic membrane. This suppressive effect was accompanied by down-regulation of alpha-smooth muscle actin, EDA spliced form of fibronectin, and integrin alpha5. It persisted even when challenged by 10 ng/ml TGF-beta1. In contrast with their counterparts grown on plastic or in collagen gel, such suppression in amniotic membrane cultures remained complete after 1 week of culturing. Cells cultured on amniotic membrane showed significantly reduced [3H]-thymidine incorporation compared to cells cultured on plastic and displayed no DNA fragmentation. These results reveal a novel mechanism by which the TGF-beta signaling system, DNA synthesis, and subsequent myofibroblast differentiation can be suppressed by an amnionic membrane matrix. This action explains in part the antiscarring results of amniotic membrane transplantation used for ocular surface reconstruction, a surgical technique applicable to other subspecialties. It may also explain in part why fetal wound healing is scarless.

Presence of vitronectin and activated complement factor C9 on ventriculoperitoneal shunts and temporary ventricular drainage catheters

OBJECT

The pathogenesis of cerebrospinal fluid (CSF) shunt infection is characterized by staphylococcal adhesion to the polymeric surface of the shunt catheter. Proteins from the CSF--fibronectin, vitronectin, and fibrinogen--are adsorbed to the surface of the catheter immediately after insertion. These proteins can interfere with the biological systems of the host and mediate staphylococcal adhesion to the surface of the catheter. In the present study, the presence of fibronectin, vitronectin, and fibrinogen on CSF shunts and temporary ventricular drainage catheters is shown. The presence of fragments of fibrinogen is also examined.

METHODS

The authors used the following methods: binding radiolabeled antibodies to the catheter surface, immunoblotting of catheter eluates, and scanning force microscopy of immunogold bound to the catheter surface. The immunoblot showed that vitronectin was adsorbed in its native form and that fibronectin was degraded into small fragments. Furthermore, the study demonstrated that the level of vitronectin in CSF increased in patients with an impaired CSF-blood barrier. To study complement activation, an antibody that recognizes the neoepitope of activated complement factor C9 was used. The presence of activated complement factor C9 was shown on both temporary catheters and shunts.

CONCLUSIONS

Activation of complement close to the surface of an inserted catheter could contribute to the pathogenesis of CSF shunt infection.

Differential regulation of keratinocyte growth factor and hepatocyte growth factor/scatter factor by different cytokines in human corneal and limbal fibroblasts

Corneal epithelial stem cells and transient amplifying cells are located in the limbal and corneal regions, respectively. In a serum-free medium with or without different cytokines, limbal fibroblasts consistently produced greater levels of keratinocyte growth factor (KGF) transcript and protein than corneal fibroblasts, whereas corneal fibroblasts produced greater levels of hepatocyte growth factor/ scatter factor (HGF/SF) transcript and protein than limbal fibroblasts. Expression of HGF/SF transcript and protein was up-regulated mildly by epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), or platelet-derived growth factor B (PDGF-BB) but markedly by interleukin-1 beta (IL-1 beta) and was more pronounced in limbal than in corneal fibroblasts. Expression of KGF transcript was down-regulated by EGF, TGF-alpha, and PDGF-BB, was markedly up-regulated by IL-1 beta, and was more pronounced in limbal than in corneal fibroblasts. Expression of KGF protein was up-regulated markedly by IL-1 beta and moderately by PDGF-BB, especially in limbal fibroblasts. TGF-beta 1 uniquely turned off transcript and protein expression of HGF/SF and KGF in corneal fibroblasts. Although its transcript levels were similarly down-regulated in limbal fibroblasts, KGF protein levels were paradoxically up-regulated by TGF-beta 1 when added alone or with TGF-alpha or IL-1 beta. These data indicate that KGF and HGF/SF, two fibroblast-derived epithelial mitogens, are expressed differentially by limbal and corneal fibroblasts and are modulated by cytokines activated during epithelial-mesenchymal interactions, suggesting that they may play a different role in modulating corneal epithelial stem cells and transient amplifying cells.

[Study on the distribution HIV-1 C subtype in Ruili and other counties, Yunnan, China]

Cooperating with CDC, USA, the Center for AIDS Surveillance, Chinese Academy of Preventive Medicine, first identified the epidemic of HIV-1 C subtype virus in China in 1994. As part of the Eighth-Five National Scientific Program and to get information about the geographical distribution of C subtype of HIV-1 and its epidemic time span in Yunnan, using specific peptide ELISA, we tested 192 anti-HIV-1 positive serums, among intravenous drug users. The results indicated that C subtype of HIV-1 started to appear in Ruili (5.1%) in 1992, and the rates were 12.9% in Ruili and 30.4% in Longchuan in 1993, up to 31.9% in Ruili and 33.3% in Longchuan in 1994. The porpotion of C subtype is increasing among the drug users by year. Whether C subtype would become the main the main epidemic subtype in this areas remains to be under observation.

Differential regulation of cytokine and receptor transcript expression in human corneal and limbal fibroblasts by epidermal growth factor, transforming growth factor-alpha, platelet-derived growth factor B, and interleukin-1 beta

PURPOSE

To explore further the significance of three patterns of cytokine dialogues that have been characterized between human corneal and limbal epithelial cells and fibroblasts.

METHODS

Northern hybridization of the transcript expression of type I cytokine receptors (EGFR, IL-1R, and PDGFR-beta), type II cytokines (bFGF, LIF, and TGF-beta 1), and type III cytokines (HGF and KGF) by human corneal and limbal fibroblasts was conducted under the modulation of TGF-alpha, PDGF-BB, IL-1 beta, and EGF (type I cytokines). The mechanism of upregulation by IL-1 beta was studied further with respect to proto-oncogene expression and under the treatment of cycloheximide and actinomycin D.

RESULTS

Results showed that EGF upregulated LIF and HGF but downregulated KGF and M-CSF. Unlike EGF, TGF-alpha upregulated additional EGFR, PDGFR-beta, bFGF, and TGF-beta 1, suggesting that although they share the same EGFR, TGF-alpha, which is produced by epithelium, is more effective in activating fibroblasts than EGF, which is present in tears. The upregulation of PDGF-BB was similar to that of TGF-alpha, except that it further stimulated IL-8, supporting their synergistic roles in promoting wound healing. Uniquely, IL-1 beta upregulated KGF expression by limbal fibroblasts more than corneal fibroblasts and IL-8 and M-CSF expression, but it downregulated PDGFR-beta. In IL-1 beta, the upregulation of cytokines and receptors was preceded by the upregulation of c-fos, c-jun, and c-myc, and it was inhibited by actinomycin D. Its upregulation of LIF was superinduced, but the upregulation of bFGF and KGF was inhibited, and that of the rest was not affected by cycloheximide.

CONCLUSIONS

These findings suggest that epithelial cells under stress or injury (producing IL-1) might preferentially activate limbal epithelial stem cells indirectly by fibroblasts and simultaneously might promote inflammation during wound healing.

Comparison between serum-free and fibroblast-cocultured single-cell clonal culture systems: evidence showing that epithelial anti-apoptotic activity is present in 3T3 fibroblast-conditioned media

PURPOSE

To compare the supporting mechanism between the serum-free and the fibroblast-cocultured single-cell clonal culture systems.

METHODS

Clonal growth, measured by colony forming efficiency (CFE) and size, was compared between rabbit corneal and limbal epithelial cells in a previously-established serum-free MCDB medium supplemented with growth factors, and in a coculture system with a feeder layer of mitomycin C-treated mouse 3T3 fibroblasts grown in the MCDB or DMEM medium plus 20% fetal bovine serum (FBS).

RESULTS

Limbal epithelial cells in the serum-free MCDB medium had a significantly lower CFE than corneal epithelial cells (p < 0.001), suggesting that this system promoted more clonal growth of corneal progenitor cells. In contrast, with cocultured 3T3 fibroblasts limbal CFE was significantly increased (p < 0.001), while corneal CFE was not changed, indicating that the 3T3 system promoted more clonal growth of limbal progenitor cells. Addition of 20% FBS in the MCDB medium cocultured with 3T3 fibroblasts significantly promoted both limbal and corneal CFEs (p < 0.001). For both cultures, switching the serum-containing MCDB medium to the serum-containing DMEM medium produced clonal growth only with cocultured fibroblasts. This epithelial growth-promoting activity was not present on the cell surface or in the extracellular matrix, but present in pre-centrifuged and prefiltered 3T3 fibroblast-conditioned media. Both growth-promoting and anti-apoptotic activities were present in fibroblast-derived serum-free conditioned media. In the presence of this anti-apoptotic activity, serum addition promoted clonal growth, and the expression of cornea-type K3 keratin in limbal colonies was negative using AE-5 monoclonal antibody.

CONCLUSIONS

Further purification and characterization of this fibroblast-derived anti-apoptotic survival factor will facilitate understanding of the mechanism by which epithelial stem cells are regulated via epithelial-mesenchymal interactions.

Comparison of protein kinase C subtype expression between normal and aniridic human ocular surfaces: implications for limbal stem cell dysfunction in aniridia

Frozen sections of corneoscleral buttons from normal and aniridic donors were stained with hematoxylin and periodic acid-Schiff, monoclonal antibodies AE-5 and AK-2 (to cornea-specific K3 and K12 keratins, respectively), and AM-3 (to conjunctival goblet cells) as well as with subtype-specific antibodies to seven different protein kinase C (PKC) subtypes, the signal transduction isoenzymes increasingly implicated in the regulation of cell growth and differentiation. Compared with the normal cornea, the aniridic cornea showed decreased AE-5 and AK-2 stainings, increased AM-3 staining, attenuated Bowman's membrane, invasion of new blood vessels, and limbal epithelial hyperplasia. In the normal tissue, the corneal epithelium expressed PKC alpha, lambda, and zeta; the limbal and conjunctival epithelia expressed additional PKC gamma. Conjunctival goblet cells expressed only PKC lambda. Within a given epithelium, different PKC subtypes had different cell-layer distributions. In the aniridic tissue, some of the four normally expressed subtypes were expressed in different cell layers, especially at the limbal region. PKC beta and PKC delta, which were normally weakly expressed, were markedly up-regulated. These results support the conclusion that the aniridic cornea does indeed manifest features of limbal stem cell deficiency with decreased corneal epithelial phenotype and increased conjunctival epithelial phenotype. Different capacities of proliferation and differentiation may be affected by the differential expression of PKC subtypes by different cell layers of normal ocular surface epithelia. The aberrant expression of PKC subtypes in aniridia may thus result in abnormal proliferation and differentiation noted in its ocular surface epithelia. Because limbal stem cells are the ultimate source of corneal proliferation and differentiation, we postulate that limbal deficiency in aniridia is a result of abnormal limbal stem cells.

Three patterns of cytokine expression potentially involved in epithelial-fibroblast interactions of human ocular surface

Signals transmitted from mesenchyme to epithelia or vice versa constitute the basis of reciprocal epithelial-mesenchymal interactions. As a first step toward understanding epithelial-mesenchymal interactions on the ocular surface where the transit amplifying cell-containing corneal epithelium is anatomically separated from the stem cell-containing limbal epithelium, we sought to characterize the expression patterns of cytokines and their receptors by primary epithelial and early-passaged fibroblast cultures of human cornea and limbus. Northern hybridization with oligonucleotide and cDNA probes to a total of 25 cytokines and 12 of their receptors revealed that the positively expressed cytokines could be divided into the following four patterns. Type I: TGF-alpha, IL-1 beta, and PDGF-B were expressed exclusively by epithelial cells but their respective receptors EGFR and IL-1R were predominantly and PDGFR-beta was exclusively expressed by fibroblasts. Type II: IGF-I, TGF-beta 1, -beta 2, LIF, and bFGF, and their receptors were expressed by both epithelial cells and fibroblasts. FGFR-1 (flg) and FGFR-2 (bek) were expressed more by fibroblasts and bFGF was expressed more by corneal than limbal epithelial cells. Type III: keratinocyte growth factor (KGF) and hepatocyte growth factor (HGF) were expressed exclusively by fibroblasts and their respective receptors, KGFR and c-met, were predominantly expressed by epithelial cells. Combined with RT-PCR, the quantity of KGF and KGFR transcripts was highest in limbal fibroblasts and epithelial cells, respectively. In contrast, the quantity of HGF and HGFR (c-met) transcripts was highest in corneal fibroblasts and epithelial cells, respectively. Type IV: M-CSF and IL-8 were expressed by fibroblasts and/or epithelial cells but their receptors were not expressed by epithelial cells nor fibroblasts, but by immune or inflammatory cells. In addition to these potential paracrine actions, autocrine actions mediated by TGF-alpha/EGFR, IL-1 beta/IL1-R, and bFGF/FGFR-1 were more expressed by corneal than limbal epithelial cells. Immunofluorescence staining on human corneoscleral cryosections confirmed that EGFR and bFGF were not expressed by the limbal basal epithelium, but expressed strongly by the corneal epithelium, a pattern consistent with Northern hybridization. These results indicate that ocular surface epithelial cells and fibroblasts can express a myriad of cytokines, among which the first three patterns constitute the network of potential epithelial-mesenchymal cytokine dialogues. The difference of certain cytokine expression between corneal and limbal regions suggests that this network participates in normal epithelial growth and differentiation, and plays an important role in wound healing.

Cohort study of HIV infection among drug users in Ruili, Longchuan and Luxi of Yunnan Province, China

In March 1992, KAP investigation and HIV blood test were carried out for 860 drug users and 82 spouses in Ruili, Luxi, Longchuan of Yunnan Province, China. The results showed that there were 285 injecting drug users (IDUs) (33.1%) among 860 drug users. Among 282 blood samples of IDUs, the HIV infection rate was 49.0%, highest in Ruili (81.8%, 63/77), then Longchuan (44.6%, 74/166), lowest in Luxi county (5.1%, 2/39). Twelve new HIV(+) were found from 75 persons, who had been tested as HIV(-) in recent two years. Sixty-two blood samples were collected among 82 spouses of IDUs with HIV(+), and 6 were HIV(+) (9.8%), with an increase of 6.7% compared with results of the investigation two years ago (3.1%, 2/64).

Multiple restricted lineages in the embryonic rat cerebral cortex

We have labelled precursor cells in the embryonic rat cerebral cortex using BAG, a retroviral vector that expresses beta-galactosidase. We had previously reported that labelled precursor cells generate clusters of labelled cells that could be classified into four types by their morphological appearance and anatomical distribution (Price and Thurlow, 1988). In this study, we have used immunohistochemistry and intracellular dye labelling to identify the cell types that make up these clusters. We discovered that clusters are almost always composed of a single cell type. In addition to clusters composed entirely of neurones, we found four different types of glial cell clusters. In the grey matter, glial clusters are composed either of protoplasmic astrocytes, or of cells that have an astrocyte morphology, but no glial filaments. In the white matter, clusters are composed of either fibrous astrocytes or oligodendocytes. Our results indicate that each of these different cortical cell types is generated from a separate population of precursor cells.

A comparison of swim-down and swim-up methods for the extraction of high motility sperm

High quality motile sperm are essential for the success of the in vitro fertilization-embryo transfer program and related procedures, for the performance of sperm antibody assays, and other in vitro tests of sperm function. Two methods for the extraction of high motility sperm, swim-down and swim-up, were compared on 30 ejaculates, and sperm motility was assessed at intervals up to 18 hours. The swim-down method was simpler, shorter, and provided a significantly better recovery of sperm with sustained high motility than did the swim-up method.

Nuclear 3,5,3'-triiodothyronine receptors (T3R) of circulating human lymphocytes in hyper- and hypothyroidism and nonthyroidal diseases

The clinical implications of nuclear T3R alterations of circulating lymphocytes in hyperthyroidism, hypothyroidism and nonthyroidal diseases were investigated. Nuclear T3R in lymphocytes was determined by radio-ligand binding analysis. The results showed that in hyper- and hypothyroid patients the nuclear affinity (Ka) for T3 was similar to that of normal subjects. In hyperthyroidism nuclear T3 maximal binding capacity (MBC) was unaltered, whereas in hypothyroidism the MBC was significantly increased. In the patients with diabetes mellitus, chronic renal failure and hepatic cirrhosis, the nuclear T3R MBC of lymphocytes was about 1.5-1.6 times of the normal controls. It was concluded that there existed hormonal regulation of nuclear T3R, and up-regulation was seen in hypothyroidism and low T3 syndrome.

[Nuclear 3,5,3'-triiodothyronine receptors in circulating human lymphocytes in normal, hyper-and hypothyroid subjects]

The relationship between nuclear receptors and thyroid function state has not been elucidated. We have determined the circulating lymphocyte nuclear T3R in normal subjects, in patients with hyper-and hypothyroidism and in hypothyroid patients on thyroid hormone substitution treatment, with 10 cases in each group. In hyperthyroid and hypothyroid patients, the nuclear affinity (Kd) for T3 was similar to that of normal subjects. In hyperthyroidism nuclear T3 MBC was unaltered, whereas in hypothyroidism the MBC was significantly increased to 8.06 +/- 0.80 fmol/micrograms DNA, being 2.1 times that of the control group. In hypothyroid patients treated with 90-120 mg desiccated thyroid extract daily the nuclear MBC was 4.34 +/- 0.72 fmol/micrograms DNA, being not different from that observed in euthyroid subjects. It was found that the nuclear T3 MBC was negatively correlated with serum levels of T3, T4, FT3, FT4 and rT3, but positively correlated with serum TSH concentration in hypothyroid patients. These results indicate hormonal modulation of the nuclear T3R which exhibits up regulation in hypothyroidism. The increase in nuclear T3R number might reflect a compensatory mechanism to the decreased serum concentrations of thyroid hormones.

Effects of hypoxia and complement activation on lung hemodynamics and fluid exchanges in unanesthetized goats

The effects of hypoxia and zymosan-activated plasma (ZAP) on lung hemodynamics and fluid exchange were studied in unanesthetized goats. Hypoxia produced a sustained increase in pulmonary arterial pressure (PPA), but had no effect on lung lymph flow and protein content. Following ZAP infusion there was an early phase of leukopenia and marked pulmonary hypertension followed by a phase characterized by a modest increase in the flow of protein-rich lung lymph. When ZAP was infused at a simulated altitude of 4,000 m, there was a further increase in PPA followed by pulmonary vasodilatation, and about 1 h later it was almost back to the control level. No obvious difference in lung lymph flow and protein content was observed between the groups treated with ZAP alone and ZAP plus hypoxia. We conclude that infusion of ZAP into hypoxic animals reduces pulmonary vasoconstriction and that the increase in pulmonary microvascular permeability associated with ZAP is not enhanced by hypoxic conditions occurring at a simulated altitude of 4,000 m.