Reproducibility in the quantification of mRNA levels by RT-PCR-ELISA and RT competitive-PCR-ELISA

Venthamarai chooranam, a polyherbal Siddha medicine, alleviates hypertension via AT₁R and eNOS signaling pathway in 2K1C hypertensive rats

The present study was aimed to scientifically demonstrate the anti-hypertensive action of Venthamarai chooranam (VMC) in renal hypertensive rats. Two Kidney One Clip (2K1C) Goldblatt model was adopted to induce hypertension in rats. Male Sprague Dawley rats (270-320 g) were randomized into sham (n = 6), vehicle-treated 2K1C (n = 9) and VMC-treated 2K1C (400 mg/kg, p.o; n = 8) and monitored for nine weeks. Systolic blood pressure (SBP), plasma nitrate/nitrite, carotid endothelial nitric oxide synthetase (eNOS), renal angiotensin type 1 receptor (AT₁R), angiotensin type 2 receptor (AT₂R), TNFα, IL-6, thioredoxin 1 (TRX1), and thioredoxin reductase 1 (TRXR1) mRNA expressions were studied. VMC upregulated eNOS expression which in turn improved plasma nitric oxide and decreased SBP in hypertensive rats. It down-regulated AT₁R and simultaneously upregulated AT₂R expression in comparison to vehicle-treated 2K1C rats. Further, renal TNFα and IL-6 expressions were down-regulated while TRX1 and TRXR1 were upregulated by VMC. VMC potentially interacts with renin-angiotensin components and endothelial functions, and thereby exerts its antihypertensive action. This is the first study to demonstrate the mechanism of anti-hypertensive action of VMC in an animal model of renovascular hypertension.

[Comparison between Real-Time PCR and Agarose Gel Electrophoresis for DNA Quantification.]

BACKGROUND

Real-time polymerase chain reaction (PCR) is generally regarded as a very accurate and time-saving method, but it is expensive to run. We evaluated the reliability of an inexpensive and a researcher-friendly gel electrophoresis-based PCR method for the quantification of mRNA, and the results were compared with those obtained by real-time PCR.

METHODS

We compared the results of relative quantification for MMP-1 measured by real-time PCR and by ethidium bromide stained-agarose gel electrophoresis after end-point PCR.

RESULTS

There was significant but very weak correlation between real-time PCR and end-point PCR for relative quantification of MMP-1 (r=0.16, P<0.01).

CONCLUSIONS

Our results suggest that the use of the gel electrophoresis-based end-point PCR is inappropriate for quantifying mRNA. Therefore, in order to confirm the result of relative quantification by end-point PCR, the newly established real-time PCR method or northern hybridization should be applied.

Antihyperglycemic effect of Annona squamosa hexane extract in type 2 diabetes animal model: PTP1B inhibition, a possible mechanism of action?

AIM

The mechanism of action of Annona squamosa hexane extract in mediating antihyperglycemic and antitriglyceridimic effect were investigated in this study.

MATERIALS AND METHODS

The effects of extract on glucose uptake, insulin receptor-β (IR-β), insulin receptor substrate-1 (IRS-1) phosphorylation and glucose transporter type 4 (GLUT4) and phosphoinositide 3-kinase (PI3 kinase) mRNA expression were studied in L6 myotubes. The in vitro mechanism of action was tested in protein-tyrosine phosphatase 1B (PTP1B), G-protein-coupled receptor 40 (GPR40), silent mating type information regulation 2 homolog 1 (SIRT1) and dipeptidyl peptidase-IV (DPP-IV) assays. The in vivo efficacy was characterized in ob/ob mice after an oral administration of the extract for 21 days.

RESULTS

The effect of extract promoted glucose uptake, IR-β and IRS-1 phosphorylation and GLUT4 and PI3 kinase mRNA upregulation in L6 myotubes. The extract inhibited PTP1B with an IC(50) 17.4 μg/ml and did not modulate GPR40, SIRT1 or DPP-IV activities. An oral administration of extract in ob/ob mice for 21 days improved random blood glucose, triglyceride and oral glucose tolerance. Further, the extract did not result in body weight gain before and after treatment (29.3 vs. 33.6 g) compared to rosiglitazone where significant body weight gain was observed (28.4 vs. 44.5 g; *P<0.05 after treatment compared to before treatment).

CONCLUSION

The results suggest that Annona squamosa hexane extract exerts its action by modulating insulin signaling through inhibition of PTP1B.

3beta-taraxerol of Mangifera indica, a PI3K dependent dual activator of glucose transport and glycogen synthesis in 3T3-L1 adipocytes

BACKGROUND

The present study focuses on identifying and developing an anti-diabetic molecule from plant sources that would effectively combat insulin resistance through proper channeling of glucose metabolism involving glucose transport and storage.

METHODS

Insulin-stimulated glucose uptake formed the basis for isolation of a bioactive molecule through column chromatography followed by its characterization using NMR and mass spectroscopic analysis. Mechanism of glucose transport and storage was evaluated based on the expression profiling of signaling molecules involved in the process.

RESULTS

The study reports (i) the isolation of a bioactive compound 3beta-taraxerol from the ethyl acetate extract (EAE) of the leaves of Mangifera indica (ii) the bioactive compound exhibited insulin-stimulated glucose uptake through translocation and activation of the glucose transporter (GLUT4) in an IRTK and PI3K dependent fashion. (iii) the fate of glucose following insulin-stimulated glucose uptake was ascertained through glycogen synthesis assay that involved the activation of PKB and suppression of GSK3beta.

GENERAL SIGNIFICANCE

This study demonstrates the dual activity of 3beta-taraxerol and the ethyl acetate extract of Mangifera indica as a glucose transport activator and stimulator of glycogen synthesis. 3beta-taraxerol can be validated as a potent candidate for managing the hyperglycemic state.

Cinnamic acid, from the bark of Cinnamomum cassia, regulates glucose transport via activation of GLUT4 on L6 myotubes in a phosphatidylinositol 3-kinase-independent manner

BACKGROUND

Cinnamomum cassia (Family: Lauraceae) is an Ayurvedic medicinal plant used traditionally for the treatment of a number of diseases, including diabetes. The hypoglycemic effect of this plant has been established in vivo. However, the effects of cinnamic acid, isolated from C. cassia, on the insulin signaling cascade in an in vitro model have not been elucidated. Hence, the aim of the present study was to evaluate the anti-diabetic effect of cinnamic acid on glucose transport by L6 myotubes.

METHODS

The mechanism of action of cinnamic acid was determined using specific targets in the insulin signaling pathway, including protein tyrosine phosphatase (PTP) 1B, phosphatidylinositol 3-kinase (PI3-K) and the glucose transporter GLUT4. After differentiation of myoblast to myotubes, the cells were serum deprived for 5 h and then treated with 1 ng/mL cinnamic acid and 50 μmol/L rosiglitazone for 18 h and 100 nmol/L insulin for 20 min for gene expression studies.

RESULTS

Expression of GLUT4 mRNA was increased following treatment of L6 myotubes with 1 ng/mL cinnamic acid. Furthermore, cinnamic acid inhibited PTP1B activity (by 96.5%), but had no significant effect on PI3-K activity.

CONCLUSION

On the basis of the results of the present study, we postulate that cinnamic acid isolated from the hydro-alcoholic extract of Cinnamomum cassia activates glucose transport by a PI3-K-independent pathway. However, the detailed mechanism of action requires further analysis.

Expression of the endocannabinoid system in human first trimester placenta and its role in trophoblast proliferation

The endocannabinoid, anandamide, which binds to two major receptor proteins, the cannabinoid receptors (CBs) 1 and 2 (CB1 and CB2), has been shown to play a role in first trimester miscarriage possibly through impairment of the developing trophoblast. Although the precise molecular mechanisms underlying this are unknown, plasma anandamide levels are known to be regulated by the progesterone-induced enzyme, fatty acid amide hydrolase (FAAH). Here, we tested the hypothesis that temporal-spatial expression of FAAH, CB1, and CB2 is regulated during early pregnancy and that anandamide detrimentally alters trophoblast proliferation. Transcripts for CB1, CB2, and FAAH were demonstrated in first trimester trophoblast extracts with only the CB1 transcript being significantly regulated. The significant 4.7-fold increase in expression at wk 10 gestation was reduced to 8.9% of the peak value by wk 12. Transcripts for CB2 showed a similar pattern of expression but were not significantly induced. By contrast, FAAH transcript levels appeared to increase toward the end of the first trimester, but again did not reach significance. These observations were supported by immunohistochemical studies that demonstrated a similar pattern of expression at the protein level, with cellular localization for all three proteins concentrated within the syncytiotrophoblast layer. Anandamide also prevented BeWo trophoblast cell proliferation in a dose-dependent manner, with a 50-60% significant inhibition of cell proliferation with concentrations in excess of 3 mum. This effect was mediated through CB2. Together, these data provide insights into how elevated plasma anandamide levels increase the risk of first trimester miscarriage.

Differing responses of human follicular and nonfollicular scalp cells in an in vitro wound healing assay: effects of estrogen on vascular endothelial growth factor secretion

Improved wound healing of hairy skin may involve mesenchymal hair follicle cells with stem cell potential and enhancement by estrogen therapy. How estrogen affects follicular dermal papilla (DP) and dermal sheath (DS) cells in wound healing is unknown. Therefore, a comparison of estradiol action on DP, DS, and corresponding interfollicular dermal fibroblasts (DF) in a scratch-wound assay was performed using matching primary cultures established from female temporo-occipital scalp. All three cell types expressed mRNA transcripts and protein for estrogen receptors alpha (ERalpha) and beta (ERbeta). DF ERalpha transcripts were half that of DP and one-third of DS cells, while DF ERbeta transcripts were two-thirds of DP and DS cells. In the scratch-wound assay all three cells types migrated at similar rates, but only the rate of DF was enhanced by estradiol. Mechanical wounding increased DNA synthesis rates of all three cell types and increased the secretion of collagen by DF and DS cells. All three secreted similar basal levels of vascular endothelial growth factor (VEGF), which was increased by wounding DF and DS cells, but not DP cells. DP cells required estradiol to increase VEGF secretion; by contrast VEGF secretion was decreased by estradiol in wounded DS cells. These results highlight differences in the responses of DF, DP, and DS cells to estradiol in a scratch-wound assay, providing further support for the dichotomy of cellular functions in the hair follicle. Further understanding of the role of estrogen in cutaneous wound healing may have important implications for the management of chronic wounds and scarring.

Withanolide induces apoptosis in HL-60 leukemia cells via mitochondria mediated cytochrome c release and caspase activation

The present study is on the growth inhibitory effect of Withania somnifera methanolic leaf extract and its active component, withanolide on HL-60 promyelocytic leukemia cells. The decrease in survival rate of HL-60 cells was noted to be associated with a time dependent decrease in the Bcl-2/Bax ratio, leading to up regulation of Bax. Both the crude leaf extract and the active component activated the apoptotic cascade through the cytochrome c release from mitochondria. The activation of caspase 9, caspase 8 and caspase 3 revealed that caspase was a key mediator in the apoptotic pathway. DNA fragmentation analysis revealed typical ladders as early as 12h indicative of caspase 3 role in the apoptotic pathway. Flow cytometry data demonstrated an increase of sub-G1 peak upon treatment by 51% at 24h, suggesting the induction of apoptotic cell death in HL-60 cells.

The importance of careful blood processing in isolation of cell-free DNA

In healthy individuals, the source of cell-free plasma DNA is predominantly apoptotic, whereas, increased plasma DNA integrity is seen in cancer patients. Therefore, it is important to carefully isolate absolutely "cell-free" plasma DNA. Plasma DNA from 30 healthy females was analyzed using 4 PCR amplicons of increasing size, comparing standard blood processing with additional centrifugation steps prior to DNA extraction. Cellular DNA contamination, indicated by positive amplicons >300 bp was eliminated only after the extra centrifugation step. This highlights the importance of careful processing in preparation of cell-free plasma DNA as a tool for cancer detection and we recommend the use of a microcentrifuge spin, prior to DNA extraction.

Dexamethasone mediates protection against acute pancreatitis via upregulation of pancreatitis-associated proteins

AIM

To examine the influence of dexamethasone on pancreatitis-associated protein (PAP) gene expression using both in vitro and in vivo models of acute pancreatitis and to study how PAP gene expression correlates with severity of pancreatitis.

METHODS

In vitro, IL-6 stimulated pancreas acinar AR42J cells were cultured with increasing concentrations of dexamethasone and assayed for PAP expression (RT-PCR). In vivo, pancreatitis was induced in rats by retrograde injection of 40 g/L taurocholate into the pancreatic duct. Animals were pretreated with dexamethasone (2 mg/kg) daily or saline for 4 d. Pancreata and serum were harvested after 24 h and gene expression levels of PAP I, II and III were measured by RT-PCR. Severity of pancreatitis was based on serum amylase, pancreatic wet weight, and histopathological score.

RESULTS

In vitro, dexamethasone and IL-6 induced a marked transcription of PAP I, II and III genes in AR42J cells at 24 h (P < 0.05 for all comparisons). In vivo, pancreas mRNA levels of PAP I, II or III increased by 2.6-fold, 1.9-fold, and 1.3-fold respectively after dexamethasone treatment, compared with saline treated animals. Serum amylase levels and edema were significantly lower in the dexamethasone group compared with the saline group. Histopathologic evaluation revealed less inflammation and necrosis in pancreata obtained from dexamethasone treated animals (P < 0.05).

CONCLUSION

Dexamethasone significantly decreases the severity of pancreatitis. The protective mechanism of dexamethasone may be via upregulating PAP gene expression during injury.

Whole blood cytokine profiles in cats infected by feline coronavirus and healthy non-FCoV infected specific pathogen-free cats

In this study, the cytokine profiles of clinically healthy cats naturally infected with feline coronavirus (FCoV), of cats with feline infectious peritonitis (FIP) and of specific pathogen-free (SPF) cats were investigated in whole blood using a traditional reverse-transcriptase polymerase chain reaction (RT-PCR) assay and a semi-quantitative method of analysis based on computerised quantification of positive bands. The low inter-assay coefficient of variation recorded demonstrated that this method is highly repeatable. Compared with SPF cats, cytokine production was upregulated in most of the samples from FCoV-positive non-symptomatic cats. The appearance of a case of FIP in the cattery was associated with an increased expression of cytokines, in particular there was an increased production of IL-1beta and IFN-gamma, suggesting that these cytokines might protect infected cats from the disease. This hypothesis was also supported by the low levels of IFN-gamma recorded in blood from cats with FIP.

The modulation of aromatase and estrogen receptor alpha in cultured human dermal papilla cells by dexamethasone: a novel mechanism for selective action of estrogen via estrogen receptor beta?

Steroid hormones have important modulatory effects on the hair follicle, but the mechanisms by which they regulate human hair growth are still poorly understood. It is now clear that there are two distinct estrogen receptors (estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta)) that bind 17beta-estradiol. Since the follicular dermal papilla is known to control hair growth, and steroid hormones regulate receptor and aromatase expression in other tissues, we tested the hypothesis that steroid hormones would similarly modulate estrogen receptor and/or aromatase expression in cultured dermal papilla cells derived from human hair follicles. Primary cultures of non-balding occipital and frontal scalp and beard dermal papilla cells (n = 10) were established. Immunocytochemical studies showed the expression of ERalpha in both the cytoplasm and nucleus, whereas ERbeta was confined to the nuclei. The cells derived from occipital scalp were also incubated for 24 hours with 10 nM of either 17beta-estradiol, estrone, testosterone, 5alpha-dihydrotestosterone, 5alpha-androstane-3alpha, 17beta-diol, 5alpha-androstane-3beta, 17beta-diol, or 100 nM tamoxifen or dexamethasone in phenol red-free, serum-free medium to measure the steady-state levels of ERalpha, ERbeta, and aromatase mRNA by semiquantitative reverse transcriptase-PCR. Although androgens and estrogens did not alter ERalpha mRNA levels, treatment with dexamethasone significantly reduced ERalpha levels to 38% of the untreated control. By contrast, ERbeta mRNA levels were unaffected by any steroid treatment. Furthermore, dexamethasone significantly stimulated the expression of aromatase mRNA approximately 9-fold. Aromatase activity, assayed by the tritiated water method, was stimulated in both frontal scalp and beard dermal papilla cell cultures by dexamethasone. These observations provide evidence for a glucocorticoid-dependent mechanism whereby the selective action of estradiol via ERbeta may be promoted. Additionally, upregulation of aromatase combined with downregulation of ERalpha provides a basis for selective action of estradiol produced locally by autocrine or paracrine mechanisms.

Trimegestone differentially modulates the expression of matrix metalloproteinases in the endometrial stromal cell

Matrix metalloproteinases (MMP) are considered to be of critical importance in the initiation of menstruation where MMP protein levels are reciprocally modulated by the actions of the gonadal steroid hormones, estradiol (E(2)) and progesterone (P4), with P4 being considered the principal suppressor of endometrial MMP expression. Trimegestone (T) is a novel progestagen that tightly controls menstruation timing and duration through mechanisms that might involve MMP suppression. Endometrial stromal cells treated with 10(-6) M E(2), P4 or T in the presence and absence of 10(-6)M RU486 showed that both T and P4 suppressed the expression of MMP-1 and MMP-3 transcripts and secreted protein, whereas MMP-9 was not produced in culture. The suppressive effect of T or P4 on MMP-1 and MMP-3 transcript levels was enhanced in the presence of E(2) and attenuated in the presence of RU486, although MMP-1 proteins were unaffected by the presence of RU486, which alone acted as a partial progesterone agonist in these cultures. Immunohistochemistry with MMP-1, MMP-3 and MMP-9-specific antibodies performed on endometrial biopsies obtained from non-treated, LH-dated, normally cycling women and endometrial biopsies obtained from postmenopausal women treated with T-based HRT showed that immunoreactive MMP-1 and MMP-3 was higher in the menstrual phase, whilst MMP-9 expression was higher in the late luteal phase (P = 0.03) and T significantly inhibited the presence of MMP-9(+) cells. These data suggest that T acts in a similar manner to P4, but causes subtle differences in expression patterns of MMPs that may explain the different clinical effect that this progestagen has on endometrial behaviour compared to P4.

The novel antifibrotic agent pirfenidone attenuates the profibrotic environment generated by calcineurin inhibitors in the rat salt-depletion model

Calcineurin inhibitors (CNIs) promote fibrosis in renal allografts by altering the dynamics of extracellular matrix (ECM) turnover. Graft structure is changed and functional disturbance may follow. This study examined the effects of an antifibrotic agent, pirfenidone, on functional, structural, and molecular markers of fibrosis in a rat model. Cyclosporine or tacrolimus were administered to salt-depleted rats, with or without varying doses of pirfenidone. Both CNIs increased serum creatinine, and pirfenidone attenuated this functional disturbance. No changes in urinary protein excretion or graft histology were observed, suggesting structural and functional alterations can be dissociated. Messenger RNA expression of pro- and antifibrotic genes affecting ECM was estimated with semiquantitative RT-PCR. Cyclosporine-induced increases in collagen III mRNA expression were attenuated by pirfenidone (500 mg/kg/d), and increases in TIMP-1 expression were reversed by all doses of pirfenidone. Matrix metalloproteinase-2 expression was decreased by cyclosporine; all doses of pirfenidone significantly reversed this effect. Tacrolimus alone decreased TGF-beta and TIMP-1 expression, suggesting some antifibrotic action; addition of pirfenidone had no further effect. The mechanism of action of pirfenidone is reversal of some CNI-induced changes in fibrotic gene expression. It also attenuates creatinine rise in salt-depleted rats in this model of CNI-induced nephrotoxicity.

The Experimental Agent Pirfenidone Reduces Pro-Fibrotic Gene Expression in a Model of Tacrolimus-Induced Nephrotoxicity

BACKGROUND

Tacrolimus nephrotoxicity is thought to contribute to renal allograft dysfunction and subsequent failure, a process that is underpinned by alterations in mRNA expression of genes involved in matrix metabolism. The new anti-fibrotic pirfenidone was tested for its potential to reverse markers of renal dysfunction.

MATERIALS AND METHODS

Rats were salt-depleted before tacrolimus and pirfenidone treatment. Serum creatinine, urinary protein/creatinine ratio, extracellular matrix deposition (ECM), and mRNA expression of genes involved in matrix turnover were assessed.

RESULTS

Tacrolimus reduced TGF-beta mRNA expression below control levels and treatment with pirfenidone at all doses did not alter this effect. Likewise, TIMP-1 mRNA expression was depressed by the addition of tacrolimus and pirfenidone caused a further decrease in expression. Collagen III, MMP-2, and MMP-9 expression was unchanged by tacrolimus, but pirfenidone reduced collagen III below control levels. ECM was slight (1-4%) and not significantly different between groups.

CONCLUSIONS

These findings suggest that pirfenidone can attenuate the limited fibrotic potential of tacrolimus.

Real-time Fluorescent PCR Techniques to Study Microbial-Host Interactions

This chapter describes how real-time polymerase chain reaction (PCR) performs and how it may be used to detect microbial pathogens and the relationship they form with their host. Research and diagnostic microbiology laboratories contain a mix of traditional and leading-edge, in-house and commercial assays for the detection of microbes and the effects they impart upon target tissues, organs, and systems. The PCR has undergone significant change over the last decade, to the extent that only a small proportion of scientists have been able or willing to keep abreast of the latest offerings. The chapter reviews these changes. It discusses the second-generation of PCR technology-kinetic or real-time PCR, a tool gaining widespread acceptance in many scientific disciplines but especially in the microbiology laboratory.

Detection of Genetically Modified Organisms in Foods by DNA Amplification Techniques

In this article, the different DNA amplification techniques that are being used for detecting genetically modified organisms (GMOs) in foods are examined. This study intends to provide an updated overview (including works published till June 2002) on the principal applications of such techniques together with their main advantages and drawbacks in GMO detection in foods. Some relevant facts on sampling, DNA isolation, and DNA amplification methods are discussed. Moreover; these analytical protocols are discuissed from a quantitative point of view, including the newest investigations on multiplex detection of GMOs in foods and validation of methods.

Deoxynivalenol-induced mitogen-activated protein kinase phosphorylation and IL-6 expression in mice suppressed by fish oil

The trichothecene mycotoxin deoxynivalenol (DON) induces IgA hyperelevation and mesangial IgA deposition in mice that mimics the early stages of human IgA nephropathy (IgAN). Among potential mediators of this disease, interleukin-6 (IL-6) is likely to play a particularly critical role in IgA elevation and disease exacerbation. Based on previous findings that dietary fish oil (FO) suppresses DON-induced IgAN, we hypothesized that FO inhibits the induction of IL-6 expression by this mycotoxin in vivo and in vitro. Mice were fed modified AIN 93G diet amended with 7% corn oil (CO) or with 1% corn oil plus 6% menhaden fish oil (FO) for up to 8 weeks and then exposed acutely to DON by oral gavage. DON-induced plasma IL-6 and splenic mRNA elevation in FO-fed mice were significantly suppressed after 8 weeks when compared to the CO-fed group. The effects of FO on phosphorylation of mitogen-activated protein kinases (MAPKs), critical upstream transducers of IL-6 up-regulation, were also assessed. DON-induced phosphorylation of extracellular signal regulated protein kinases 1 and 2 (ERK1/2) and c-Jun N-terminal kinases 1 and 2 (JNK1/2) was significantly suppressed in spleens of mice fed with FO, whereas p38 was not. Splenic COX-2 mRNA expression, which has been previously shown to enhance DON-induced IL-6, was also significantly decreased by FO, whereas plasma levels of the COX-2 metabolite, prostaglandin E2, were not affected. To confirm in vivo findings, the effects of pretreatment with the two primary n-3 PUFAs in FO, eicosapentaenoic acid (20:5[n-3]; EPA) and docosahexaenoic acid, (22:6[n-3]; DHA), on DON-induced IL-6 expression were assessed in LPS-treated RAW 264.7 macrophage cells. Consistent with the in vivo findings, both EPA and DHA significantly suppressed IL-6 superinduction by DON, as well as impaired DON-induced ERK1/2 and JNK1/2 phosphorylation. In contrast, the n-6 PUFA arachidonic acid (20:4[n-3]) had markedly less effects on these MAPKs. Taken together, the capacity of FO and its component n-3 PUFAs to suppress IL-6 expression as well as ERK 1/2 and JNK 1/2 activation might explain, in part, the reported suppressive effects of these lipids on DON-induced IgA nephropathy.

Real-time PCR in the microbiology laboratory

Use of PCR in the field of molecular diagnostics has increased to the point where it is now accepted as the standard method for detecting nucleic acids from a number of sample and microbial types. However, conventional PCR was already an essential tool in the research laboratory. Real-time PCR has catalysed wider acceptance of PCR because it is more rapid, sensitive and reproducible, while the risk of carryover contamination is minimised. There is an increasing number of chemistries which are used to detect PCR products as they accumulate within a closed reaction vessel during real-time PCR. These include the non-specific DNA-binding fluorophores and the specific, fluorophore-labelled oligonucleotide probes, some of which will be discussed in detail. It is not only the technology that has changed with the introduction of real-time PCR. Accompanying changes have occurred in the traditional terminology of PCR, and these changes will be highlighted as they occur. Factors that have restricted the development of multiplex real-time PCR, as well as the role of real-time PCR in the quantitation and genotyping of the microbial causes of infectious disease, will also be discussed. Because the amplification hardware and the fluorogenic detection chemistries have evolved rapidly, this review aims to update the scientist on the current state of the art. Additionally, the advantages, limitations and general background of real-time PCR technology will be reviewed in the context of the microbiology laboratory.

Vitamin C supplementation in normal subjects reduces constitutive ICAM-1 expression

Regulation of monocyte adhesion molecule gene expression is via redox sensitive transcription factors. We have investigated whether dietary antioxidant supplementation with vitamin C (250 mg/day) can modulate monocyte ICAM-1 expression in healthy male subjects with low plasma vitamin C at baseline. In a randomised, double-blind, crossover study, monocyte ICAM-1 mRNA was analysed using quantitative reverse transcriptase PCR. Protein was determined by flow cytometry (monocytes) and ELISA (plasma). Monocyte numbers were unaltered by supplementation. Subjects with low plasma vitamin C (<50 microM) prior to supplementation expressed higher levels of monocyte ICAM-1mRNA, and showed a significant (50%) reduction in ICAM-1mRNA expression after 6 weeks of 250 mg/day vitamin C supplementation (p<0.05). This was paralleled by a reduction in sICAM-1 (p<0.05). For the first time, these results show that dietary vitamin C can modulate monocyte ICAM-1 gene expression in vivo, where regulation of gene expression represents a novel mechanism for benefit from dietary antioxidants.

Fibrosis-associated gene expression in renal transplant glomeruli after acute renal allograft rejection

BACKGROUND

Acute allograft rejection is thought to be a risk factor for chronic allograft nephropathy, the cardinal features of which are vasculopathy, interstitial fibrosis and glomerulosclerosis. Fibrosis-associated genes might act as ad interim surrogate markers for chronic allograft nephropathy. The aim of this study was to determine mRNA expression of fibrosis-associated genes in glomeruli plucked from protocol renal transplant biopsies, in patients with or without a history of acute rejection.

METHODS

A consecutive series of 52 patients (31 male, 21 female) was assessed. Donor categories were cadaveric, living related or asystolic. Transplant recipients received either cyclosporin- or tacrolimus-based immunosuppression. Patients routinely underwent percutaneous needle-core renal transplant biopsy at 1 week, and 3 and 6 months. Acute rejection episodes were confirmed histologically and treated with intravenous methylprednisolone, or antithymocyte globulin if steroid resistant. Individual glomeruli were plucked and total mRNA was extracted. Fibrosis-associated genes were amplified by reverse transcriptase-polymerase chain reaction (PCR) and quantified by enzyme-linked immunosorbent assay.

RESULTS

The expression of both collagen type III (mean 0.42 versus 0.31 arbitrary units of PCR products corrected for a housekeeping gene) and collagen IV (mean 0.46 versus 0.42 arbitrary units) at 6 months did not differ between recipients who experienced acute rejection episodes and those who were free from rejection. There was also no significant difference between groups in terms of mRNA expression of collagen IValpha2, matrix metalloproteinase 2, tissue inhibitor of matrix metalloproteinases 1 and 2, transforming growth factor beta or tenascin.

CONCLUSION

These results suggest that acute rejection episodes do not increase the expression of fibrosis-associated genes in glomeruli from renal transplant biopsies.

Expression of a novel immunoglobulin gene SNC73 in human cancer and non-cancerous tissues

AIM: To investigate the expression of immunoglobulin gene SNC73 in malignant tumors and non-cancerous normal tissues.

METHODS: Expression level of SNC73 in tumors and non-cancerous tissues from the same patient was determined by reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay (RT-PCR-ELISA) in 90 cases of malignant tumors, including colorectal cancer, gastric cancer, breast cancer, lung cancer and liver cancer. Analysis on the correlation of SNC73 expression with sex, age, site, grade of differentiation, depth of invasion, and metastases in colorectal cancer patients was made.

RESULTS: Expression level of SNC73 in non-cancerous colorectal mucosa and colorectal cancerous tissues was 1.234 ± 0.842 and 0.737 ± 0.731, respectively (P < 0.01), with the mean ratio of 7.134 ± 14.092 (range, 0.36-59.54). Expression of SNC73 showed no significant difference among gastric cancer, breast cancer, lung cancer and liver cancer when compared with non-cancerous tissues (P > 0.05). No correlation was found between SNC73 expression level and various clinicopathological factors, including sex, age, site, grade of differentiation, depth of invasion and metastases of CRC patients.

CONCLUSION: Down-regulation of SNC73 expression may be a relatively specific phenomenon in colorectal cancer. SNC73 is a potential genetic marker for the carcinongenesis of colorectal cancer. The relationship of SNC73 expression and carcinogenesis of colorectal cancer merits further study.

The impact of cyclosporine dose reduction with or without the addition of rapamycin on functional, molecular, and histological markers of chronic allograft nephropathy

BACKGROUND

Overexposure to cyclosporine is a risk factor for chronic allograft nephropathy (CAN) and dose reduction has been advocated. The purpose of this study was to determine the impact of adding the non-nephrotoxic immunosuppressant, rapamycin, after cyclosporine dose reduction in renal-allograft recipients with CAN.

METHODS

Thirty-one patients with biopsy-confirmed CAN were prospectively randomized to receive a 40% cyclosporine dose reduction with (rapamycin, n=16) or without (control, n=15) the addition of rapamycin 2 mg/day. Renal function and side-effect parameters were assessed. Patients had renal allograft biopsies taken at recruitment and after 6 months. Glomeruli were isolated from these and underwent total mRNA extraction followed by RT-PCR-ELISA to assess transforming growth factor-beta1, collagen III, TIMP-1, TIMP-2, and matrix metalloproteinase-2 expression. Samples were also stained with Sirius red and the percentage interstitial volume fraction quantified by computerized histomorphometric analysis. Data are presented as mean (+/-SD).

RESULTS

Patient characteristics and cyclosporine trough levels after dose reduction (rapamycin 68 [+/-21] vs. control 56 [+/-19] ng/mL, P=NS) were similar in both groups. Rapamycin patients had a significant fall in Cr-51 radioisotope glomerular filtration rate (31.6 [+/-8.9] to 27.3 [+/-8.6] mL/min, P<0.01) that was not significant in controls (29.5 [+/-10.4] to 27.0 [+/-8.0] mL/min, P=NS). Transforming growth factor-beta1 expression fell over time in control but remained constant in rapamycin patients. Conversely collagen III expression increased over the 6-month follow-up in rapamycin patients but not in controls. Both had comparable increases in TIMP-1 and matrix metalloproteinase-2 but only rapamycin patients developed a significant increase in TIMP-2. Sirius red-stained interstitial volume fraction fell over the study in controls (15.3-11.2%, P=0.06) but not in rapamycin patients (16.2-16.3%, P=NS).

CONCLUSION

Rapamycin (2 mg/day) did not improve functional, molecular, or histological outcome in patients with CAN after cyclosporine dose reduction. Further studies involving larger numbers of patients are necessary to confirm these findings.

Cyclooxygenase-2 mediates interleukin-6 upregulation by vomitoxin (deoxynivalenol) in vitro and in vivo

Interleukin-6 (IL-6) is a central mediator of immunotoxicity that is associated with exposure to the trichothecene vomitoxin (VT). The purpose of this investigation was to test the hypothesis that the inducible cyclooxygenase-2 (COX-2) and its metabolites contribute to VT-induced IL-6 upregulation. VT at 100 to 250 ng/ml readily induced COX-2 protein expression in the RAW 264.7 murine macrophage cell line. Superinduction of lipopolysaccharide (LPS)-mediated IL-6 production by VT in these cells was significantly reduced by the COX inhibitors indomethacin and NS-398, whereas the inhibitors did not affect direct induction of IL-6 by LPS alone. Mice that had been gavaged orally with 5 and 25 mg/kg VT exhibited elevated COX-2 mRNA expression in Peyer's patches and spleen with peak induction occurring 2 h after VT exposure. IL-6 mRNA was also induced by VT in vivo, however, peak expression occurred from 2 to 4 h after toxin exposure, suggesting that maximal COX-2 gene upregulation preceded or was concurrent with that for IL-6. Also consistent with a putative contributory role for COX-2 was the finding that both induction of splenic IL-6 mRNA and serum IL-6 by VT were significantly reduced by pretreating mice with the COX inhibitors indomethacin or NS-398. Finally, COX-2 knockout mice showed significantly reduced splenic IL-6 mRNA and serum IL-6 responses to oral VT exposure compared to their parental wild type. Taken together, these in vitro and in vivo data suggest that VT-induced COX-2 gene expression and resultant COX-2 metabolites contributed, in part, to subsequent upregulation of IL-6 gene expression, which has been previously shown to be a hallmark of VT-mediated immunotoxicity.

Delay in processing porcine whole blood affects cytokine expression

Quantification of cytokine messenger ribonucleic acid (mRNA) in blood samples has become an important tool in the investigation of immune cell activation in a variety of clinical settings. It has been shown that the method of sample collection and processing influences the levels of several cytokine mRNAs. Therefore, it is generally accepted that blood samples for analysis of cytokine expression be processed as soon as possible and under standardised conditions. Since immediate sample processing is not always possible, we investigated the effect of different storage conditions (room temperature (Rt) and 4 degrees C) and storage times (1, 2, 4, 6 and 24 h) on the mRNA level of different cytokines (IL-1alpha, IL-2, IL-6, IL-8, IL-10, IFN-gamma), as well as the IL-2 receptor (IL-2R) in porcine whole blood samples (n=8). Quantification of cytokine expression was performed using simultaneous reverse transcription PCR (RT-PCR) combined with the expression of the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a reference. Our data demonstrate that delays in sample processing longer than 1 h result in significant changes of the mRNA levels of individual cytokines. Expression of the monokines IL-1alpha, IL-6 and IL-10 were increased by storage at both room temperature and 4 degrees C. Expression of IL-8 was increased only in the samples stored at room temperature, and expression of IFN-gamma was raised exclusively in the samples stored at 4 degrees C. We conclude that porcine blood samples should be processed within 2 h to prevent undesired stimulatory effects on the cytokine expression pattern. However, if only selected cytokines are investigated, the undesired effects of prolonged storage can be selectively suppressed by choosing the appropriate temperature of sample storage.

Primary breast myoepithelial cells exert an invasion-suppressor effect on breast cancer cells via paracrine down-regulation of MMP expression in fibroblasts and tumour cells

In normal breast and ductal carcinoma in situ, myoepithelial cells form an incomplete layer separating the epithelial compartment from the stromal environment. Transition to invasive disease is marked by penetration of the myoepithelial-basement membrane (BM) interface. One mechanism involved in tumour invasion is breakdown of extracellular matrices by matrix metalloproteinases (MMPs). It was hypothesized that myoepithelial cells may modulate tumour invasion by controlling MMP gene expression, both in tumour cells and in peri-ductal fibroblasts. To investigate this, myoepithelial cells from normal breast were purified and characterized and their effect on tumour cell invasive potential was assessed. The effect on MMP gene expression of breast cancer cells cultured alone or in combination with primary normal breast fibroblasts was also analysed using RT-PCR with ELISA quantitation, with zymographic analysis to measure enzyme activity. Normal breast myoepithelial cells significantly reduced invasion by the breast cancer cell lines MCF-7, T47D, MDA-MB 231, and MDA-MB 468 when they were cultured alone or in the presence of a fibroblast population. Reduced invasion was associated with changes in MMP gene expression. In those tumour cells expressing MMP, there was a significant down-regulation of MMP-2 (MDA-MB 468, p<0.001), MMP-9 (MDA-MB 231, p=0.05; MDA-MB 468, p<0.001), and MT1-MMP (p<0.001 for both MDA-MB 231 and MDA-MB 468). Myoepithelial cells also caused a significant decrease in MMP gene expression in co-cultured fibroblasts. Furthermore, this was associated with reduced gelatinolytic activity as identified by zymography. This study demonstrates for the first time that primary myoepithelial cells from normal breast reduce breast cancer cell invasion and that this is mediated via modulation of both tumour cell and fibroblast function. This emphasizes the importance of the myoepithelial cell in controlling the breast microenvironment and focuses on the potential significance of the loss of this population with disease progression.

Decreased expression of membrane IL-5 receptor alpha on human eosinophils: I. Loss of membrane IL-5 receptor alpha on airway eosinophils and increased soluble IL-5 receptor alpha in the airway after allergen challenge

IL-5 is a key cytokine for eosinophil maturation, recruitment, activation, and possibly the development of inflammation in asthma. High concentrations of IL-5 are present in the airway after Ag challenge, but the responsiveness of airway eosinophils to IL-5 is not well characterized. The objectives of this study were to establish, following airway Ag challenge: 1) the expression of membrane (m)IL-5Ralpha on bronchoalveolar lavage (BAL) eosinophils; 2) the responsiveness of these cells to exogenous IL-5; and 3) the presence of soluble (s)IL-5Ralpha in BAL fluid. To accomplish these goals, blood and BAL eosinophils were obtained from atopic subjects 48 h after segmental bronchoprovocation with Ag. There was a striking reduction in mIL-5Ralpha on airway eosinophils compared with circulating cells. Furthermore, sIL-5Ralpha concentrations were elevated in BAL fluid, but steady state levels of sIL-5Ralpha mRNA were not increased in BAL compared with blood eosinophils. Finally, BAL eosinophils were refractory to IL-5 for ex vivo degranulation, suggesting that the reduction in mIL-5Ralpha on BAL eosinophils may regulate IL-5-mediated eosinophil functions. Together, the loss of mIL-5Ralpha, the presence of sIL-5Ralpha, and the blunted functional response (degranulation) of eosinophils to IL-5 suggest that when eosinophils are recruited to the airway, regulation of their functions becomes IL-5 independent. These observations provide a potential explanation for the inability of anti-IL-5 therapy to suppress airway hyperresponsiveness to inhaled Ag, despite a reduction in eosinophil recruitment.

Oestrogen receptors alpha and beta differ in normal human breast and breast carcinomas

The identification of a second oestrogen receptor, oestrogen receptor (ER) beta, has led to a need to assess the relative importance of the classical ERalpha and ERbeta in human breast and breast carcinomas. ERalpha and ERbeta mRNA was assessed in 61 carcinomas, 8 benign breast lesions, and 30 samples of normal breast using reverse transcriptase (RT)-nested polymerase chain reaction (PCR). Immunohistochemical analysis of ERalpha and ERbeta was performed in 62 carcinomas, the 38 non-malignant breast tissues, and 32 normal breast samples with menstrual cycle data. ERalpha mRNA was detected in 92% of breast cancers, with ERbeta mRNA (wild-type and/or variant form) in 85%; 72% had ERalpha protein, 62% progesterone receptor (PgR), and 32% ERbeta. ERalpha protein had a strong correlation with grade; ERbeta did not, although it was present in three of four grade I carcinomas and in special types. There was no correlation between the presence of ERalpha and ERbeta protein. In non-malignant breast, similar expression of ERalpha and beta was observed, apart from expression of ERbeta in stromal cells and myoepithelium, the latter being confirmed by RT-PCR and western blotting. There were differences in ERalpha in relation to the menstrual cycle but not PgR or ERbeta. The findings indicate a need to understand the role and regulation of ERbeta in normal breast and the reason for its down-regulation in mammary carcinogenesis.

Effects of the combination of rapamycin with tacrolimus or cyclosporin on experimental intimal hyperplasia

BACKGROUND

Allograft vasculopathy remains the leading cause of late allograft failure following transplantation and can be inhibited by the antiproliferative drug rapamycin. This study assessed the efficacy of combining rapamycin therapy with calcineurin inhibition.

METHODS

Male Sprague-Dawley rats received rapamycin 0.05 mg/kg daily and either tacrolimus 0.1 mg/kg or cyclosporin 5 mg/kg daily, and findings were compared with those in an untreated control group. Animals underwent left common carotid artery balloon angioplasty; the artery was explanted after 2 weeks. Morphometric analysis was performed on transverse sections and the intima : media ratio was calculated. Profibrotic gene expression was measured with competitive reverse transcriptase-polymerase chain reaction at 14 and 28 days. Proliferation was determined with proliferating cell nuclear antigen at 14 and 28 days. Extracellular matrix deposition was quantified with Sirius red.

RESULTS

The combination of rapamycin and tacrolimus was associated with the greatest reduction in intimal thickening. Furthermore, treatment with rapamycin and tacrolimus significantly attenuated extracellular matrix deposition compared with rapamycin and cyclosporin (P < 0.02).

CONCLUSION

The effects of rapamycin in combination with tacrolimus were better than those observed with rapamycin and cyclosporin.

Flow Cytometric Quantification of Competitive Reverse Transcription-PCR Products

Background: Competitive PCR of reverse transcribed mRNA sequences is used to quantify transcripts, but the usual approaches are labor-intensive and time-consuming. We describe the non-gel-based quantification of competitive reverse transcription (RT)-PCR products with use of microparticles and flow cytometry.

Methods: PCR products of a target sequence and an internal control sequence (competitor) were labeled during PCR using digoxigenin (DIG)- and dinitrophenol (DNP)-labeled primer, respectively, allowing specific binding to microparticles coated with the corresponding antibody. Both amplification products were biotinylated to enable fluorescence labeling with streptavidin-R-phycoerythrin. The mean fluorescence intensity of each microparticle population, corresponding to the amount of bound PCR product, was measured in a flow cytometer. We constructed microparticles coated with antibodies against DIG and DNP to specifically capture PCR products derived from target and competitor sequences, respectively.

Results: As required for a reliable competitive PCR assay, nearly identical kinetics were found for the amplification of target and competitor sequences when using only one competitive primer. The method was applied to examine interleukin-8 expression in human lymphocytes after x-irradiation. One hour after irradiation, the concentration of transcripts decreased by half.

Conclusions: The flow cytometric assay for the quantification of competitive RT-PCR products avoids additional hybridization steps and antibody labeling. The use of paramagnetic microparticles would also enable the complete automation of this method.

Renal transplant fibrosis correlates with intragraft expression of tissue inhibitor of metalloproteinase messenger RNA

BACKGROUND

Chronic renal allograft nephropathy is characterized by an abnormal accumulation of extracellular matrix proteins in the glomeruli and tubulo-interstitium. The aim of this study was to determine the relationship between intragraft expression of the genes controlling the accumulation of extracellular matrix and the development of chronic renal allograft nephropathy in human renal transplants.

METHODS

Forty renal allografts with stable renal function were biopsied 6 months after transplantation. Single glomeruli were plucked from the surface of these protocol biopsies and total messenger RNA (mRNA) was extracted. Reverse transcriptase-polymerase chain reaction was used to study the intragraft expression of several fibrosis-associated genes (collagen III, collagen IValpha2, matrix metalloproteinase (MMP) 2, tissue inhibitors of metalloproteinases (TIMPs) 1 and 2, tenascin and transforming growth factor (TGF) beta1). The level of tubulo-interstitial fibrosis was measured by quantitative immunostaining of collagen III.

RESULTS

There were positive correlations between the level of tubulo-interstitial collagen III immunostaining and intragraft expression of the genes for TIMP-1 (rs= 0.70, P < 0.02) and TIMP-2 (rs = 0.59, P < 0.02). Interstitial fibrosis was also strongly correlated with the levels of TGF-beta mRNA (rs = 0.67, P < 0.002). Finally, TIMP-1 expression increased with TGF-beta expression (rs = 0.77, P < 0.002).

CONCLUSION

Failure of extracellular matrix degradation may be an important molecular mechanism in the pathogenesis of chronic renal allograft damage.

Endotoxin potentiation of trichothecene-induced lymphocyte apoptosis is mediated by up-regulation of glucocorticoids

Exposure to bacterial endotoxin (lipopolysaccharide, LPS) is quite common and may increase human susceptibility to chemical-induced tissue injury. The purpose of this study was to identify mechanisms by which LPS potentiates lymphoid tissue depletion in B6C3F1 mice exposed to the common food-borne trichothecene mycotoxin, vomitoxin (VT). As demonstrated by DNA fragmentation and flow cytometric analysis, apoptosis in thymus, Peyer's patches, and bone marrow was marked in mice 12 h after administering Escherichia coli LPS (0.1 mg/kg body wt ip) concurrently with VT (12.5 mg/kg body wt po), whereas apoptosis in control mice or mice treated with either toxin alone was minimal. Based on observed increases in tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6 serum concentrations following LPS and VT cotreatment, the roles of these cytokines in apoptosis potentiation were assessed. Injection with rolipram, an inhibitor of TNF-alpha expression, or use of IL-6 knockout mice was ineffective at impairing thymic apoptosis induction by the toxin cotreatment, suggesting that these cytokines did not mediate LPS potentiation. Toxin cotreatment increased splenic cyclooxygenase-2 mRNA expression, suggesting possible involvement of prostaglandins in apoptosis. However, indomethacin, a broad spectrum inhibitor of cyclooxygenases, failed to block thymus apoptosis. Toxin cotreatment increased serum corticosterone and, furthermore, RU 486, a glucocorticoid receptor antagonist, significantly abrogated apoptosis in thymus, Peyer's patches, and bone marrow following LPS + VT exposure. The results presented herein and the known capacity of glucocorticoids to cause apoptosis indicate that hypothalamic-pituitary-adrenal axis plays a key role in LPS potentiation of trichothecene-induced lymphocyte apoptosis.

Pirfenidone inhibits early myointimal proliferation but has no effect on late lesion size in rats

AIMS

intimal hyperplasia is mediated by smooth muscle cell proliferation, migration and deposition of extracellular matrix. The anti-fibrotic agent pirfenidone has been shown to inhibit pro-fibrotic growth factors in non-vascular inflammatory models. This study investigated the effect of the novel anti-fibrotic agent pirfenidone on the development of neointima.

METHODS

male Sprague-Dawley rats received either standard diet or diet supplemented with pirfenidone (250, 500, 1000 mg/kg/day). Animals underwent left common carotid balloon angioplasty and were explanted at 4, 8, 14 and 28 days and analysed for intimal thickening, pro-fibrotic gene expression, extracellular matrix deposition and metalloproteinase activity.

RESULTS

neointimal thickness was significantly reduced in a dose-dependent manner at 14 days; pirfenidone 250 mg/kg (p<0.005), pirfenidone 500 mg/kg (p<0.001), pirfenidone 1 g/kg ( p<0.001). There were no significant differences in intimal thickening at 28 days. Expression of MMP-2, MMP-9, TIMP-1, collagen III and TGF-beta were all significantly inhibited at 14 days. Both collagen III expression and ECM deposition were reduced at 28 days ( p<0.05 and <0.002 respectively).

CONCLUSION

pirfenidone reduces expression of MMPs governing smooth muscle cell proliferation and migration (MMP-2 and 9), and genes favouring ECM accumulation (TIMP-1 and collagen III). This study shows that inhibition of MMP activity is not sufficient to inhibit late lesion size.

Programmed cell death of keratinocytes culminates in apoptotic secretion of a humectant upon secretagogue action of acetylcholine

The programmed cell death of the stratified squamous epithelial cells comprising human epidermis culminates in abrupt transition of viable granular keratinocytes (KC) into dead corneocytes sloughed by the skin. The granular cell-corneocyte transition is associated with a loss in volume and dry cell weight but the mechanism for and biological significance of this form of keratinocyte apoptosis remain obscure. We show that terminally differentiated KC extrude into the intercellular spaces of living epidermis the cytoplasmic buds containing randomly congregated components of the cytosol as well as filaggrin, a precursor of the natural moisturizing factor. The discharge of secretory product is reminiscent of holocrine secretion, suggesting the term ‘apoptotic secretion’ for this novel, essential step in the process of cornification. The secretory product may become a part of the glycocalyx (a.k.a. ‘intercellular cement substance’ of epidermis) and serve as a humectant that counterbalances the osmotic pressure imposed by the natural moisturizing factor located in the stratum corneum comprised by corneocytes. The apoptotic secretion commences upon secretagouge action of acetylcholine which is synthesized and released by KC. A combination of a cholinergic nicotinic agonist and a muscarinic antagonist which increases intracellular calcium levels is required to trigger the apoptotic secretion. Analysis of the relative amounts of cholinergic enzymes and receptors expressed by KC capable of secretion and the pharmacological profiles of secretion regulation revealed an upward concentration gradient of free acetylcholine in epidermis which may provide for its unopposed secretagogue action via the m1 muscarinic and the (α)7, and (α)9 nicotinic receptor types expressed by KC at the latest stage of their development in the epidermis.

Aberrant in vivo T helper type 2 cell response and impaired eosinophil recruitment in CC chemokine receptor 8 knockout mice

Chemokine receptors transduce signals important for the function and trafficking of leukocytes. Recently, it has been shown that CC chemokine receptor (CCR)8 is selectively expressed by Th2 subsets, but its functional relevance is unclear. To address the biological role of CCR8, we generated CCR8 deficient (-/-) mice. Here we report defective T helper type 2 (Th2) immune responses in vivo in CCR8(-/)- mice in models of Schistosoma mansoni soluble egg antigen (SEA)-induced granuloma formation as well as ovalbumin (OVA)- and cockroach antigen (CRA)-induced allergic airway inflammation. In these mice, the response to SEA, OVA, and CRA showed impaired Th2 cytokine production that was associated with aberrant type 2 inflammation displaying a 50 to 80% reduction in eosinophils. In contrast, a prototypical Th1 immune response, elicited by Mycobacteria bovis purified protein derivative (PPD) was unaffected by CCR8 deficiency. Mechanistic analyses indicated that Th2 cells developed normally and that the reduction in eosinophil recruitment was likely due to systemic reduction in interleukin 5. These results indicate an important role for CCR8 in Th2 functional responses in vivo.

RT-PCR ELISA method for the analysis of neurotrophin mRNA expression in brain and peripheral tissues

The levels of nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) in brain and periphery are susceptible to changes during development and as result of different physiopathological conditions, such as stress and aging and during the onset and progression of neurological and autoimmune diseases. Despite the sensitive methods for measurement of neurotrophin protein levels in different tissues, no easily applicable methods to evaluate changes in the level of NGF and BDNF mRNA expression within physiological range have been described. This study reports the development of a reproducible and simple procedure for measurement of neurotrophin mRNA expression in brain and peripheral tissues based upon an enzyme linked immunosorbent assay (ELISA) detection system of reverse transcriptase-polymerase chain reaction (RT-PCR) products. The major advantages of this RT-PCR ELISA procedure is to allow the co-amplification of diverse mRNAs starting from small amounts of tissues; to contemporaneously test a large number of samples; to be rapid and to use only commercial reagents and widely available equipment. The procedure could also be useful in studies addressed to measure the pattern of expression of molecules involved in the pathogenesis of neurodegenerative and inflammatory diseases, such as neuropeptides and cytokines.

Differential effects of cyclosporin and tacrolimus on the expression of fibrosis-associated genes in isolated glomeruli from renal transplants

BACKGROUND

Chronic allograft nephropathy is characterized by an excessive accumulation of extracellular matrix proteins leading to glomerular and interstitial fibrosis. The aim of this study was to determine the effects of two different immunosuppressive agents (cyclosporin and tacrolimus) on the expression of the genes controlling extracellular matrix deposition in renal transplant glomeruli.

METHODS

Fifty-one renal transplant recipients were randomized to receive immunosuppression with either microemulsion cyclosporin or tacrolimus. Isolated glomeruli were plucked from protocol transplant biopsies performed 1 week, 3 months and 6 months after transplantation. Expression of the genes for collagen IValpha2, collagen III, matrix metalloproteinase 2, tissue inhibitor of metalloproteinases (TIMP) 1 and TIMP-2, tenascin and transforming growth factor (TGF) beta1 was studied by quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

The expression of messenger RNA (mRNA) for collagen III and TIMP-1 was significantly higher in patients receiving cyclosporin therapy than in those having tacrolimus (P < 0.01); this finding was accounted for by differences in the biopsy material at 1 week. A significant difference in collagen III, TIMP-1 and TIMP-2 mRNA expression was also detected between patients depending on the source of renal donor (cadaveric or living). There were no significant differences in the level of glomerular TGF-beta1.

CONCLUSION

The data provide new in vivo evidence that tacrolimus may exert a less fibrogenic influence on transplant glomeruli than cyclosporin.

Tacrolimus has less fibrogenic potential than cyclosporin A in a model of renal ischaemia-reperfusion injury

BACKGROUND

Cyclosporin is associated with significant chronic nephrotoxicity, manifest in the long term mainly as renal fibrosis. There have been claims that tacrolimus is a less fibrotic drug than cyclosporin, and this study was designed to determine the effect of the two drugs on the expression of fibrosis-associated genes.

METHODS

Male Wistar rats underwent clamping of the right renal pedicle for 45 min together with left nephrectomy; this model has previously been shown to be associated with upregulation of fibrosis-associated genes. Experimental groups (six animals per group) received cyclosporin A 10 mg/kg daily, tacrolimus 0.2 mg/kg daily or no treatment. Animals were killed at 16 weeks, and the renal cortical expression of fibrosis-associated genes was studied by means of quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

Tacrolimus-treated animals developed significantly less proteinuria and had lower serum creatinine levels than those receiving cyclosporin. Tacrolimus administration also significantly reduced the expression of transforming growth factor beta and tissue inhibitor of metalloproteinases 1, both the products of genes associated with fibrosis. Although cyclosporin treatment reduced levels of the matrix-degrading enzymes, matrix metalloproteinase (MMP) 2 and MMP-9, this was not statistically significant.

CONCLUSION

Tacrolimus has less nephrotoxicity than cyclosporin in this model. It also appears to have less fibrogenic potential, and this may have implications for the choice of long-term immunosuppressant in renal transplantation.

Expression of oestrogen receptor alpha variants in non-malignant breast and early invasive breast carcinomas

Oestrogen receptor (ER) alpha variants have been described in normal breast and breast carcinomas, but their presence in a range of benign conditions and in small early invasive breast carcinomas has not been considered. Cryostat tissue sections from 19 normal and proliferative breast lesions and 44 carcinomas 15 mm and less in size detected by mammographic screening were screened for ERalpha splice variants using reverse transcriptase-nested PCR. The carcinomas were assessed for mutation by single-stranded conformational polymorphism analysis and variant forms/band shifts were sequenced. ERalpha was detected in all 19 non-malignant cases and exon 7-deleted variants were found in 16 of them. Three cases showed weak expression of exon 5, and two of exon 3 variants. There was no relationship between the presence of variants and the extent of proliferative change, ER status or age. ERalpha mRNA was not detected in two carcinomas; exon 3 deletions were found in four (9. 5%) of the other carcinomas, exon 5 in two (4.8%), and exon 7 in 11 (26.2%), with two variants in four carcinomas and a total of 29.5% of all cases having detectable variants. Two point mutations were found in one, which was a tubular carcinoma. Variant forms were identified in carcinomas of all sizes (bar<10 mm) but were more frequent in those of 15 mm. There was no relationship with type, grade or receptor status. The main difference between non-malignant breast and early invasive cancers related to exons 3 and 5. The findings suggest that ERalpha variants are not involved in breast cancer development but occur with tumour progression and may be a consequence rather than a cause.

Molecular changes in extracellular matrix turnover after renal ischaemia-reperfusion injury

BACKGROUND

Renal ischaemia-reperfusion (IR) injury is an inevitable consequence of transplantation and contributes to later graft fibrosis. This study aimed to elucidate the possible mechanisms by studying the expression of genes associated with extracellular matrix (ECM) turnover.

METHODS

Male Wistar rats underwent laparotomy, clamping of the right renal pedicle for 45 min, and left nephrectomy. Control animals underwent left nephrectomy only, or had no operation. Animals were killed at 8, 16 and 24 weeks and messenger RNA was extracted from renal tissue. Genes of interest were amplified and then quantified in an enzyme-linked immunosorbent assay system with levels expressed as a ratio to a known housekeeping gene (GAPDH).

RESULTS

Experimental animals developed progressive proteinuria from 16 weeks onwards. At 8 weeks after IR injury, gene levels of matrix metalloproteinase (MMP) 2, an ECM-degrading enzyme, were significantly increased. Levels then fell progressively. This was associated with increasing expression of tissue inhibitor of metalloproteinases (TIMP) 1, an inhibitor of MMP-2, and of transforming growth factor (TGF) beta, a profibrotic cytokine, by 24 weeks following injury.

CONCLUSION

These results suggest that, after an initial phase of increased ECM turnover following IR injury, the balance turns towards one of reduced degradation. This is likely to be an important mechanism in the subsequent development of fibrosis.

Inactive matrix metalloproteinase 2 is a normal constituent of human glomerular basement membrane. An immuno-electron microscopic study

Remodelling of the extracellular matrix requires tight control not only of matrix synthesis, but also of matrix degradation. Control of matrix degradation is achieved mainly through the matrix metalloproteinase (MMP) enzymes. In the glomerulus, MMP-2 and MMP-9 are believed to be particularly important, as they have activity against type IV collagen. This study has demonstrated by immuno-electron microscopy that most of the immunoreactivity for MMP-2 in the normal glomerulus is located within the glomerular basement membranes and mesangial matrix. mRNA for MMP-2 is also detectable in normal glomeruli, but the other main gelatinase, MMP-9, could not be localized by immuno-electron microscopy. In the normal glomerulus, it seemed likely that MMP-2 is present in an inactive form. To confirm this, in situ zymography was carried out using frozen sections of normal kidney. Baseline activity of normal kidney was relatively weak, but this was dramatically increased by chemical activation of metalloproteinases. The results imply that MMP-2, in an inactive form, is a normal constituent of the extracellular matrix and glomerular basement membranes. Activation would presumably render the matrix 'self-degrading'; membrane-bound MMPs (MT-MMPs) seem particularly likely to be involved in leukocyte penetration of basement membranes in inflammation.

Competitive cytokeratin 19 RT-PCR for quantification of breast cancer cells in blood cell suspensions

Detection of residual tumor cells in BM and PBPC products has been correlated with worse outcome of breast cancer patients. Still, there is a considerable demand for studies investigating the influence of the actual tumor cell number on prognosis, as quantification routinely has been cumbersome and time consuming and, thus, was evaded. We developed and evaluated a competitive RT-PCR-ELISA assay for cytokeratin 19 (CK19) with standard curve quantification that allows quantification of multiple samples within a working day; mRNA isolation, RT-PCR reaction, and automated ELISA detection were carried out using commercial kits. Results were expressed as OD420nm ratios of CK19 and an internal competitor. Values were then converted into tumor cell numbers using a standard curve of MCF-7 tumor cells. The assay had high specificity because of primers and capture probes with great heterogeneity to both published pseudogenes, which was confirmed by BLAST sequence alignment. We achieved a sensitivity of detecting 1 tumor cell per 10(6) mononuclear cells (MNC). Between-batch precision (n = 8) for quantification was consistent and reasonable, with a coefficient of variation around 25%. Therefore, this assay should be suitable and sufficient for routine quantification of tumor cell numbers in BM or PBPC samples.

Down-regulation of the endoplasmic reticulum chaperone GRP78/BiP by vomitoxin (Deoxynivalenol)

The mechanisms by which trichothecene mycotoxins cause immunological effects in leukocytes such as cytokine up-regulation, aberrant IgA production, or apoptotic cell death are not fully understood. In the present study, mRNA differential display analysis was used to evaluate changes in gene expression induced by the trichothecene vomitoxin (VT or deoxynivalenol) in a T-cell model, the murine EL-4 thymoma, that was stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin (ION). Ten differentially expressed fragments of cDNA were isolated and sequenced and three of these were identified as the known genes GRP78/BiP, P58(IPK), and RAD17. Most notably, expression of GRP78/BiP (a 78-kDa glucose-regulated protein), a stress-response gene induced by agents or conditions that adversely affect endoplasmic reticulum (ER) function, was found to decrease in VT-exposed cells. Competitive RT-PCR analysis revealed that 250 ng/ml VT decreased GRP78/BiP mRNA expression in both unstimulated and PMA/ION-stimulated EL-4 cells at 6 and 24 h after VT treatment. Western blotting confirmed that VT (50 to 1000 ng/ml) also significantly diminished GRP/BiP protein levels in a dose-response manner in PMA/ION-stimulated cells. GRP78/BiP has been shown to play a role in regulation of protein folding and secretion, and to protect cells from apoptosis. When PMA/ION-stimulated cells were incubated with 50 to 1000 ng/ml VT for 24 h, 200-bp DNA laddering, a hallmark of apoptosis, increased in a dose-dependent manner. In addition to GRP78, mRNA expression of the cochaperone P58(IPK), which is the 58-kDa cellular inhibitor of the double-stranded RNA-regulated protein kinase (PKR), was also shown to be suppressed by VT-treatment. GRP78 and P58(IPK) are critical for maintenance of cell homeostasis and prevention of apoptosis. The down-regulation of these molecular chaperones by VT represent a novel observation and has the potential to impact immune function at multiple levels.