The Role of the Tyrosine-Based Sorting Signals of the ORF3a Protein of SARS-CoV-2 on Intracellular Trafficking, Autophagy, and Apoptosis

The open reading frame 3a (ORF3a) is an accessory transmembrane protein that is important to the pathogenicity of SARS-CoV-2. The cytoplasmic domain of ORF3a has three canonical tyrosine-based sorting signals (YxxΦ; where x is any amino acid and Φ is a hydrophobic amino acid with a bulky -R group). They have been implicated in the trafficking of membrane proteins to the cell plasma membrane and to intracellular organelles. Previous studies have indicated that mutation of the 160YSNV163 motif abrogated plasma membrane expression and inhibited ORF3a-induced apoptosis. However, two additional canonical tyrosine-based sorting motifs (211YYQL213, 233YNKI236) exist in the cytoplasmic domain of ORF3a that have not been assessed. We removed all three potential tyrosine-based motifs and systematically restored them to assess the importance of each motif or combination of motifs that restored efficient trafficking to the cell surface and lysosomes. Our results indicate that the YxxΦ motif at position 160 was insufficient for the trafficking of ORF3a to the cell surface. Our studies also showed that ORF3a proteins with an intact YxxΦ at position 211 or at 160 and 211 were most important. We found that ORF3a cell surface expression correlated with the co-localization of ORF3a with LAMP-1 near the cell surface. These results suggest that YxxΦ motifs within the cytoplasmic domain may act cooperatively in ORF3a transport to the plasma membrane and endocytosis to lysosomes. Further, our results indicate that certain tyrosine mutants failed to activate caspase 3 and did not correlate with autophagy functions associated with this protein.

SARS-CoV-2 Harnesses Host Translational Shutoff and Autophagy To Optimize Virus Yields: the Role of the Envelope (E) Protein

The SARS-CoV-2 virion is composed of four structural proteins: spike (S), nucleocapsid (N), membrane (M), and envelope (E). E spans the membrane a single time and is the smallest, yet most enigmatic of the structural proteins. E is conserved among coronaviruses and has an essential role in virus-mediated pathogenesis. We found that ectopic expression of E had deleterious effects on the host cell as it activated stress responses, leading to LC3 lipidation and phosphorylation of the translation initiation factor eIF2α that resulted in host translational shutoff. During infection E is highly expressed, although only a small fraction is incorporated into virions, suggesting that E activity is regulated and harnessed by the virus to its benefit. Consistently, we found that proteins from heterologous viruses, such as the γ1 34.5 protein of herpes simplex virus 1, prevented deleterious effects of E on the host cell and allowed for E protein accumulation. This observation prompted us to investigate whether other SARS-CoV-2 structural proteins regulate E. We found that the N and M proteins enabled E protein accumulation, whereas S did not. While γ1 34.5 protein prevented deleterious effects of E on the host cells, it had a negative effect on SARS-CoV-2 replication. The negative effect of γ1 34.5 was most likely associated with failure of SARS-CoV-2 to divert the translational machinery and with deregulation of autophagy. Overall, our data suggest that SARS-CoV-2 causes stress responses and subjugates these pathways, including host protein synthesis (phosphorylated eIF2α) and autophagy, to support optimal virus replication. IMPORTANCE In late 2019, a new β-coronavirus, SARS-CoV-2, entered the human population causing a pandemic that has resulted in over 6 million deaths worldwide. Although closely related to SARS-CoV, the mechanisms of SARS-CoV-2 pathogenesis are not fully understood. We found that ectopic expression of the SARS-CoV-2 E protein had detrimental effects on the host cell, causing metabolic alterations, including shutoff of protein synthesis and mobilization of cellular resources through autophagy activation. Coexpression of E with viral proteins known to subvert host antiviral responses such as autophagy and translational inhibition, either from SARS-CoV-2 or from heterologous viruses, increased cell survival and E protein accumulation. However, such factors were found to negatively impact SARS-CoV-2 infection, as autophagy contributes to formation of viral membrane factories and translational control offers an advantage for viral gene expression. Overall, SARS-CoV-2 has evolved mechanisms to harness host functions that are essential for virus replication.

The envelope proteins from SARS-CoV-2 and SARS-CoV potently reduce the infectivity of human immunodeficiency virus type 1 (HIV-1)

BACKGROUND

Viroporins are virally encoded ion channels involved in virus assembly and release. Human immunodeficiency virus type 1 (HIV-1) and influenza A virus encode for viroporins. The human coronavirus SARS-CoV-2 encodes for at least two viroporins, a small 75 amino acid transmembrane protein known as the envelope (E) protein and a larger 275 amino acid protein known as Orf3a. Here, we compared the replication of HIV-1 in the presence of four different β-coronavirus E proteins.

RESULTS

We observed that the SARS-CoV-2 and SARS-CoV E proteins reduced the release of infectious HIV-1 yields by approximately 100-fold while MERS-CoV or HCoV-OC43 E proteins restricted HIV-1 infectivity to a lesser extent. Mechanistically, neither reverse transcription nor mRNA synthesis was involved in the restriction. We also show that all four E proteins caused phosphorylation of eIF2-α at similar levels and that lipidation of LC3-I could not account for the differences in restriction. However, the level of caspase 3 activity in transfected cells correlated with HIV-1 restriction in cells. Finally, we show that unlike the Vpu protein of HIV-1, the four E proteins did not significantly down-regulate bone marrow stromal cell antigen 2 (BST-2).

CONCLUSIONS

The results of this study indicate that while viroporins from homologous viruses can enhance virus release, we show that a viroporin from a heterologous virus can suppress HIV-1 protein synthesis and release of infectious virus.

The Envelope Proteins from SARS-CoV-2 and SARS-CoV Potently Reduce the Infectivity of Human Immunodeficiency Virus type 1 (HIV-1)

Background

Viroporins are virally encoded ion channels involved in virus assembly and release. Human immunodeficiency virus type 1 (HIV-1) and influenza A virus encode for viroporins. The human coronavirus SARS-CoV-2 encodes for at least two viroporins, a small 75 amino acid transmembrane protein known as the envelope (E) protein and a larger 275 amino acid protein known as Orf3a. Here, we compared the replication of HIV-1 in the presence of four different β-coronavirus E proteins.

Results

We observed that the SARS-CoV-2 and SARS-CoV E proteins reduced the release of infectious HIV-1 yields by approximately 100-fold while MERS-CoV or HCoV-OC43 E proteins restricted HIV-1 infectivity to a lesser extent. Mechanistically, neither reverse transcription nor mRNA synthesis was involved in the restriction. We also show that all four E proteins caused phosphorylation of eIF2-α at similar levels and that lipidation of LC3-I could not account for the differences in restriction. However, the level of caspase 3 activity in transfected cells correlated with HIV-1 restriction in cells. Finally, we show that unlike the Vpu protein of HIV-1, the four E proteins did not significantly down-regulate bone marrow stromal cell antigen 2 (BST-2).

Conclusions

The results of this study indicate that while viroporins from homologous viruses can enhance virus release, we show that a viroporin from a heterologous virus can suppress HIV-1 protein synthesis and release of infectious virus.

How FtsEX localizes to the Z ring and interacts with FtsA to regulate cell division

In Escherichia coli, FtsEX, a member of the ABC transporter superfamily, is involved in regulating the assembly and activation of the divisome to couple cell wall synthesis to cell wall hydrolysis at the septum. Genetic studies indicate FtsEX acts on FtsA to begin the recruitment of the downstream division proteins but blocks septal PG synthesis until a signal is received that divisome assembly is complete. However, the details of how FtsEX localizes to the Z ring and how it interacts with FtsA are not clear. Our results show that recruitment of FtsE and FtsX is codependent and suggest that the FtsEX complex is recruited through FtsE interacting with the conserved tail of FtsZ (CCTP), thus adding FtsEX to a growing list of proteins that interacts with the CCTP of FtsZ. Furthermore, we find that the N-terminus of FtsX is not required for FtsEX localization to the Z ring but is required for its functions in cell division indicating that it interacts with FtsA. Taken together, these results suggest that FtsEX first interacts with FtsZ to localize to the Z ring and then interacts with FtsA to promote divisome assembly and regulate septal PG synthesis.

Analysis of herpes simplex type 1 gB, gD, and gH/gL on production of infectious HIV-1: HSV-1 gD restricts HIV-1 by exclusion of HIV-1 Env from maturing viral particles

BACKGROUND

We previously showed that the gM of HSV-1 could restrict the release of infectious HIV-1 from cells. In this study, we analyzed if the four HSV-1 glycoproteins (gD, gB, and gH/gL), which are the minimum glycoproteins required for HSV-1 entry, restricted the release of infectious HIV-1.

RESULTS

Of these four glycoproteins, gD and gH/gL restricted the production of infectious HIV-1 from cells transfected with an infectious molecular clone of HIV-1 (strain NL4-3) while gB had no significant effect. Pulse-chase analyses indicated that gD did not affect the biosynthesis and processing of gp160 into gp120/gp41, the transport of the gp120/gp41 to the cell surface, or the release of HIV-1 particles from the cell surface. Our analyses revealed that gD was incorporated into HIV-1 virus particles while gp120/gp41 was excluded from released virus particles. Truncated mutants of gD revealed that the cytoplasmic domain was dispensable but that a membrane bound gD was required for the restriction of release of infectious HIV-1. Finally, cell lines expressing gD also potently restricted the release of infectious virus.

CONCLUSIONS

Due to its ability to exclude HIV-1 gp120/gp41 from maturing virus, gD may provide a useful tool in deciphering mechanisms of Env incorporation into maturing virus particles.

Quantitative analysis of the extent of heavy-metal contamination in soils near Picher, Oklahoma, within the Tar Creek Superfund Site

The Tri-State Mining District of Missouri, Kansas and Oklahoma was the site of large-scale mining operations primarily for lead and zinc until the mid-1950s. Although mining across the area has ceased, high concentrations of heavy metals remain in the region's soil and water systems. The town of Picher, Ottawa County, OK, lies within this district and was included in the Tar Creek Superfund Site by the U.S. Environmental Protection Agency in 1980 due to extensive contamination. To elucidate the extent of heavy-metal contamination, a soil-chemistry survey of the town of Picher was conducted. Samples (n = 111) were collected from mine tailings, locally known as chat, in Picher and along cardinal-direction transects within an 8.05-km radius of the town in August 2015. Samples were analyzed for soil pH, moisture, and metal content. Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) analyses of 20 metals showed high concentrations of lead (>1000 ppm), cadmium (>40 ppm) and zinc (>4000 ppm) throughout the sampled region. Soil moisture content ranged from 0.30 to 35.9%, and pH values ranged from 5.14 to 7.42. MANOVA of metal profiles determined that soils collected from the north transect and chat were significantly different (p < 0.01) than other sampled directions. Lead, cadmium and zinc were correlated with one another. These data show an unequal distribution of contamination surrounding the Picher mining site. Mapping heavy-metal contamination in these soils represents the first step in understanding the distribution of these contaminants at the Picher mining site.

[A Problematic Case: Removal of a Broken Cannulated Tibial Nail]

We present a case illustrating a simple and safe technique for the removal of a broken cannulated tibial nail after a pseudarthrosis of a lower leg shaft fracture. A 3 mm Ball-Tip guide wire was inserted into the proximal and the distal segment of the nail. A 2.5 mm tip-flattened second wire was forwarded into the distal segment pushing the Ball-Tip guide wire out of the axis and blocking it. This way the Ball-Tip could act as a hook and consecutively could be knocked back with an impactor forceps removing the complete nail. An exchange nailing was performed with a reamed AO standard nail and the further course was uneventful with a healed fracture after 12 months.

Notizen: Anthracene and its Argon Complexes, Spectra and Lifetimes

Fluorescence excitation spectra and fluorescence lifetimes at specific wavelengths are reported for anthracene and anthracene-argon complexes in a supersonic jet. At low argon pressures, complexes are observed with lifetimes and transition energies which are not dependent on the argon pressure.

At high pressures, the lifetimes reach a limiting value while the wavelength maximum continues to red shift within the pressure range observed. The possible relationship to solvent or matrix effects on a central ion are discussed.

Expression of erythropoietin and angiogenic growth factors following inner ear injury of newborn rats

Recently we have demonstrated that recombinant human erythropoietin (EPO) protects neurosensory hair cells in the organotypic culture of the organ of Corti by reducing apoptosis and necrosis. In the present study, we tested the hypothesis that EPO may be involved in reparative angiogenesis. We analyzed in parallel the endogenous erythropoietin (Epo) mRNA expression and that of Epo receptor (Epor) and of genes associated with angiogenesis in the organ of Corti, the modiolus and the stria vascularis using real time reverse transcription polymerase chain reaction and microarray. We compared the expression levels of freshly prepared tissue (control) and tissue cultured for 24 h under normoxia or hypoxia. The basal expression of Epo- and Epor mRNA in controls of all regions was very low. However, after 24 h in culture, a 20-100 fold increase of these two transcripts was measured. In culture, the vascular endothelial growth factor and the Cxcr4 (the receptor for the stromal cell-derived factor-1, Sdf-1) mRNA levels, were found to be increased and the Sdf-1 mRNA level to be decreased. Changes in mRNA expression occurred in all pathways activated in non-erythroid cells by the application of EPO (phosphoinositide 3-kinase/serine-threonine protein kinase B, Janus-type protein tyrosine kinase 2/signal transducer and activator of transcription 3, and the mitogen activated protein kinase). These data suggest that the neuroprotective effect of EPO may include at least two molecular events, the decrease of hair cell death rate and the induction of angiogenic genes.

DNA preservation: a microsatellite-DNA study on ancient skeletal remains

To determine the effect of environmental factors on the preservation of DNA, archeological teeth of approximately similar age but greatly differing site milieu were examined for DNA content. The complex relational system of locational milieu of the samples was reduced to its essential and, at the same time, easily measurable factors. These are temperature, humidity, pH value, the geochemical properties of the soil, the amount of postmortal organic substances and the general degree of microbial infestation in the respective soil. The relative DNA content in the samples was established by determining the rate of successful polymerase chain reaction (PCR) amplifications. Differences in quantity and quality of the results are attributed to the respective prevailing environmental factor or to the respective storage conditions. Dryness, low temperature and absence of microorganisms favors the preservation of DNA. The bioapatite of bones and teeth, like the DNA, are preserved under neutral or slightly alkaline conditions. Brief storage at room temperature does not affect the amount of amplifiable DNA but does affect the reproducibility of the results. Long storage outside a lab freezer reduces the amount and the reproducibility of DNA amplifications in ancient specimens.

Comparison of human COP9 signalsome and 26S proteasome lid'

The human core COP9 signalosome consists of eight subunits which have been identified, cloned and sequenced. The components of COP9 signalosome possess homologies with eight non-ATPase regulatory subunits of the 26S proteasome. These polypeptides of the 19S regulator form a reversibly binding subcomplex called the 'lid'. We isolated the 'lid' from human red blood cells and compared it with the COP9 signalosome complex. In addition to the non-ATPase regulatory polypeptides, we found a high molecular mass ATPase copurifying with the human 'lid'. The COP9 signalosome-associated kinase activity is either not at all or only weakly affected by common kinase inhibitors such as 1-(5-Isoquinolinesulfonyl)-2-methyl-piperazine (H7), 5,6-dichloro-1-beta-D-ribofuranosyl-benzimidazole (DRB) or Wortmannin. Curcumin, a tumor suppressor and effector of AP-1 activation, is a potent inhibitor of the COP9 signalosome kinase activity with a Ki of about 10 microM. Since curcumin is known as an inhibitor of the c-Jun N-terminal kinase (JNK) signaling pathway acting upstream of the MAP kinase kinase kinase level, one site of action of the COP9 signalosome might be proximal to regulators on that level.

Metabolic rates of 4-hydroxynonenal in tubular and mesangial cells of the kidney

The degradation of the lipid peroxidation product 4-hydroxynonenal (HNE) in primary cultures of kidney tubular and mesangial cells was determined. Using various initial concentrations of the aldehyde a decline of cellular viability was found. Mesangial cells were more susceptible to the toxic effects of HNE. In consumption studies of HNE the decline of the exogenously added aldehyde was comparable in both cell types after addition of 10 and 1 micromol HNE/l. After addition of 100 micromol/l aldehyde a drastically lower HNE degrading capacity was found in mesangial cells as compared to tubular cells. The loss in the HNE degrading capacity was accompanied by an increased formation of HNE-protein aggregates as demonstrated by immunoblots. Therefore, we concluded that the low ability of mesangial cells to degrade HNE may be a factor of the toxicity of free radicals on the kidney.

[Gerontology--research topics and prospects from the anthropology viewpoint]

Topics on gerontology are grossly under-represented in the German anthropological field of research. Nevertheless, new establishments of distinct research centres in the gerontological area indicate a trend towards innovative and interdisciplinary research. Up to now, anthropology has contributed relatively few studies to gerontological questions. Considering the increasing social importance of gerontological issues, the present paper attempts to present research fields and perspectives that are relevant to anthropological studies in gerontology. Three subject areas are addressed: (1) current involvement of anthropology in gerontological research, (2) evaluation of prospects for future anthropological studies in gerontology, and (3) general objectives as well as specific research areas under special consideration of applied issues.

Periodate-oxidized ATP stimulates the permeability transition of rat liver mitochondria

Periodate-oxidized ADP (oADP)2 and periodate-oxidized ATP (oATP) stimulate the permeability transition in energized rat liver mitochondria measured as the Ca2+-efflux induced by Ca2+ and Pi. In the presence of Mg2+ and Pi, mitochondria lose intramitochondrial adenine nucleotides at a slow rate. oATP induces a strong decrease of the matrix adenine nucleotides which is inhibited by carboxyatractyloside. Under these conditions, Mg2+ prevents the opening of the permeability transition pore. EGTA prevents the Pi-induced slow efflux of adenine nucleotides, but is without effect on the oATP-induced strong decrease of adenine nucleotides. This oATP-induced strong adenine nucleotide efflux is inhibited by ADP. oATP reduces the increase of matrix adenine nucleotides occurring when the mitochondria are incubated with Mg2+ and ATP. This effect of oATP is also prevented by carboxyatractyloside. oATP is not taken up by the mitochondria. It is suggested that oATP induces a strong efflux of matrix adenine nucleotides by the interaction with the ADP/ATP carrier from the cytosolic side. The induction of the mitochondrial permeability transition by oADP and oATP is attributed to two mechanisms-a strong decrease in the intramitochondrial adenine nucleotide content, especially that of ADP, and a stabilization of the c-conformation of the ADP/ATP carrier.

Quantification of matrix metalloproteinases and tissue inhibitors of metalloproteinase in prostatic tissue: analytical aspects

BACKGROUND

The balance between matrix metalloproteinases (MMP) and the tissue inhibitors of metalloproteinases (TIMP) has been seen as important during tumor invasion and progression. The determination of these components needs a special strategy of tissue preparation. This analytical problem has not been considered for prostatic tissue.

METHODS

We adapted an extraction method consisting of two extraction steps with 0.25% Triton X-100/CaCl2 solution and two heat extraction steps at 60 degrees C for 4 min. This combination allowed a complete extraction of MMP (measured as enzyme activity) and TIMP-1 (measured with an ELISA test) from cancerous and normal prostatic tissue samples.

RESULTS

The median values for cancerous vs. normal MMPs (50.8 mU/g wet tissue and 1,580 mU/g protein vs. 88.8 and 2,497) and TIMP-1 (4.49 micrograms/g wet tissue and 96.7 micrograms/g protein vs. 12.4 and 237.8) were significantly lower, whereas the respective ratios for MMP/ TIMP-1 (11.1 vs. 4.0 on wet weight and 15.5 vs. 5.3 on protein basis) were significantly higher.

CONCLUSIONS

An optimized extraction procedure was elaborated for determining MMPs and TIMP-1 in prostatic tissue samples. The increased ratio of MMP/TIMP-1 can be interpreted as an indicator of the imbalance between MMP and TIMP, characteristic of prostate carcinoma tissue.

Differential response of oxygen radical metabolism in rat heart, liver and kidney to cyclosporine A treatment

OBJECTIVE AND DESIGN

The study was designed to elucidate whether cyclosporine A (Cy A) induces oxidative stress in heart, liver and kidney.

MATERIAL AND TREATMENT

Male Wistar rats were treated with NaCl (n = 7), cremophor (vehicle for Cy A: n = 7) and 30 mg/kg b.w. Cy A in cremophor (n = 7) daily for 4 weeks.

METHODS

Oxidized (GSSG) and reduced (GSH) glutathione, lipid peroxides and superoxide dismutase were measured in the organs.

RESULTS

Increases in GSSG [nmol/mg prot.] and a compensatory rise in total GSH [nmol/mg prot.] indicating Cy A-induced oxidative stress were found in kidney (0.39 +/- 0.09 vs. 0.47 +/- 0.14 vs. 0.64 +/- 0.18; 20.71 +/- 3.86 vs. 21.07 +/- 3.86 vs. 28.14 +/- 3.37) and liver (0.51 +/- 0.11 vs. 0.51 +/- 0.09 vs. 0.65 +/- 0.25; 33.35 +/- 5.06 vs. 32.88 +/- 5.12 vs. 44.12 +/- 6.06) but not in heart.

CONCLUSION

Cy A-induced oxidative stress may contribute to the hepatotoxicity and nephrotoxicity of this drug. After heart transplantation, accelerated allograft atherosclerosis limits transplantation success. We did not find any evidence that Cy A induces oxidative stress in the heart which might favour atherogenesis.

Betaine improves the PCR amplification of GC-rich DNA sequences

Betaine improves the co-amplification of the two alternatively spliced variants of the prostate-specific membrane antigen mRNA as well as the amplification of the coding cDNA region of c-jun. It is suggested that betaine improves the amplification of these genes by reducing the formation of secondary structure caused by GC-rich regions and, therefore, may be generally applicable to ameliorate the amplification of GC-rich DNA sequences.

Elimination of serum free and total prostate-specific antigen after radical retropubic prostatectomy

Elimination kinetics of serum total and free prostate-specific antigen were studied for a ten days course after radical retropubic prostatectomy on 11 patients suffering from organ confined prostate cancer. Samples were taken before operation, immediately after finishing the operation and 1, 2, 3, 4, 5, 6 h after prostatectomy and then once a day for the following ten days. The measurements were performed with AxSym assays from Abbott Laboratories. The elimination of both total and free prostate-specific antigen followed a biphasic kinetics. In the fast phase, the average of the individual elimination half-lives of total and free prostate-specific antigen amounted to 6.3 h (SD = 6.1 h; range: 0.55 to 37.1 h) and 0.57 h (SD = 0.18 h; range: 0.22 to 0.89 h), respectively. In the slow phase, total prostate-specific antigen disappeared with an average half-life of 85.6 h (SD = 11 h; range: 47.2 to 261.7 h) and free prostate-specific antigen with an average half-life of 14.4 h (SD = 10.4 h; range: 2.4 to 30.3 h). These results might be significant for the use of free and total prostate-specific antigen and its ratio as a diagnostic and prognostic tool.

Individual assessment of antihypertensive response by self-starting cumulative sums

A self-interpreted control chart, on an individualized basis, assesses the effect of a switch from beta-blockers to an angiotensin-converting enzyme (ACE)-inhibitor in a patient with occasional blood pressure (BP) excess. In dense and long data series, the BP and heart rate (HR) of this patient respond to the change in treatment by the test criterion of a self-starting Cumulative Sum (cusum), which reaches values outside a decision interval with a lowering of BP and an increase in HR and vice versa, at least for BP, after treatment cessation. Thereafter, minimal sampling requirements are sought in the same data by applying the same control chart approach to decimated data. Skeleton sampling schemes in a system of chronobiologic self-analysis and interpretation of manually recorded data obtained at strategically placed times (established on the basis of data decimations) could complement control charts that are used on a home computer or preferably would be built into the output of ambulatory monitors used at the outset as a minimum and routinely as an optimum.

Increased analytical sensitivity of RT-PCR of PSA mRNA decreases diagnostic specificity of detection of prostatic cells in blood

The diagnostic specificity of the detection of disseminated prostatic cells by reverse-transcriptase polymerase chain reaction (RT-PCR) of PSA mRNA was investigated. A sensitive nested PCR was developed. In blood samples from 10 healthy female and 10 healthy male persons examined by RT-PCR, mRNA of PSA was detected 3 times in each group. In the groups of patients suffering from benign prostate hyperplasia and prostate cancer, 6 of 11 and 5 of 12, respectively, gave positive RT-PCR results. With increasing analytical sensitivity of the RT-PCR of PSA mRNA, the diagnostic specificity of the assay is decreased. Further development of this diagnostic method requires the introduction of the quantitative PCR which may make possible discrimination between prostatic and non-prostatic source of PSA mRNA by quantification.

Antioxidant enzymes in malignant prostate cell lines and in primary cultured prostatic cells

The antioxidant enzymes catalase, glutathione reductase (GR), glutathione S-transferase (GST), glutathione peroxidase (GPx), and superoxide dismutase (SOD) were determined in the androgen-response LNCaP and androgen-nonresponsive PC-3 and DU 145 cells as well as in prostatic epithelial cell cultures of benign and malignant human prostatic tissue. There were no differences between the enzyme activities of the human primary cell cultures from cancerous tissue and their normal counterparts. The enzyme activities of the three permanent cell lines were either higher (SOD, catalase, GR) or lower (GST, GPx) than in the primary cell cultures. In LNCaP cells catalase and GR were significantly higher, GST, in contrast, was significantly lower than in PC-3 and DU 145 cells. GST in PC-3 and DU 145 cells, and SOD in all the three cell lines showed no significant differences. Catalase, GPx and GR values were significantly different in the three permanent cell lines. The different enzymatic equipment of the prostate cancer cell lines provides the basis for experimental testing of new concepts of cancer treatment with the help of systematic modulations of the antioxidant defence systems in prostate cancer.

Non-hyperbolic calcium calibration curve of Fura-2: implications for the reliability of quantitative Ca2+ measurements

The fluorescence probe Fura-2 is widely applied for the quantitative determination of cellular free Ca2+ concentration. Generally, a hyperbolic calibration curve has been taken as a basis. The in vitro calibration of Fura-2 performed with free Ca2+ concentrations ranging from 10 nM to about 9 mM demonstrates a non-hyperbolic curve. Assuming two Ca2+ binding sites of Fura-2 dissociation constants of 190 nM and 176 microM were estimated. The analysis of the calibration data by the equation introduced by Grynkiewicz et al. [Grynkiewicz G., Poenie M., Tsien R.Y. A new generation of Ca2+ indicators with greatly improved fluorescence properties. J Biol Chem 1985; 260: 3440-3450] shows that the inclusion of Ca2+ concentrations in the range of the low-affinity binding site leads to an overestimation of the dissociation constant normally used within this method. The Rmax value conventionally estimated at a nominal saturating free Ca2+ concentration increases if concentrations in the range of the low-affinity binding site are selected for this purpose. Provided that millimolar free Ca2+ concentrations are applied for the determination of Rmax, the experimentally-estimated free Ca2+ concentration should be considerably lower than the real cellular concentration. This bias is especially to be expected if free Ca2+ concentrations exceeding the high-affinity Ca2+ binding site of Fura-2 are measured. With the use of approximately 10 microM free Ca2+ for the determination of Rmax the contribution of the low-affinity binding site is negligible. Data for cellular free Ca2+ calculated on the basis of Rmax values estimated with Ca2+ concentrations in the millimolar range should be considered with caution.

Analytical performance and clinical validity of two free prostate-specific antigen assays compared

We compared two recently introduced commercial assays (CanAg and Immulite) for measuring free prostate-specific antigen (f-PSA), total PSA (t-PSA), and the ratio of t-PSA/f-PSA (f-PSA%) in control materials and sera of 54 healthy men, 50 patients with benign prostatic hyperplasia (BPH), and 45 patients with prostate cancer (PCa). The lower detection limits for f-PSA were 0.038 microgram/L and 0.004 microgram/L for the CanAg and Immulite assays, respectively. The within-run and between-day precisions of the Immulite assay were < 5%; the CanAg assay showed a poorer precision. Whereas f-PSA values differed between controls and patients but not between BPH and PCa patients, the f-PSA% values were lower in PCa patients than in BPH patients and controls. The receiver-operating characteristic (ROC) curve showed an improved diagnostic power of f-PSA% compared with t-PSA to discriminate between BPH and PCa. Discrimination limits of 16% (CanAg assay), and 15% (Immulite assay) are recommended for f-PSA%.

Analytical performance and clinical validity of two free prostate-specific antigen assays compared

We compared two recently introduced commercial assays (CanAg and Immulite) for measuring free prostate-specific antigen (f-PSA), total PSA (t-PSA), and the ratio of t-PSA/f-PSA (f-PSA%) in control materials and sera of 54 healthy men, 50 patients with benign prostatic hyperplasia (BPH), and 45 patients with prostate cancer (PCa). The lower detection limits for f-PSA were 0.038 microgram/L and 0.004 microgram/L for the CanAg and Immulite assays, respectively. The within-run and between-day precisions of the Immulite assay were &lt; 5%; the CanAg assay showed a poorer precision. Whereas f-PSA values differed between controls and patients but not between BPH and PCa patients, the f-PSA% values were lower in PCa patients than in BPH patients and controls. The receiver-operating characteristic (ROC) curve showed an improved diagnostic power of f-PSA% compared with t-PSA to discriminate between BPH and PCa. Discrimination limits of 16% (CanAg assay), and 15% (Immulite assay) are recommended for f-PSA%.

Strip test for the quick detection of increased concentrations of prostate-specific antigen in blood

We tested the performance of the new immunochemical membrane test BioSign PSA for detecting serum concentrations of prostate-specific antigen > 4 micrograms/l. Measurements were simultaneously performed on 161 serum samples, using the strip test and three quantitative assays of prostate specific antigen (Tandem-E, IMx, LIA-mat). Based on the upper reference limit of 4 micrograms/l, 11-37% of the results obtained with the BioSign test were false-negative and 4-15% were false-positive, compared with the data of the three quantitative assays. It is concluded that the BioSign test in its present form does not satisfactorily differentiate between prostate-specific antigen concentrations above and below 4 micrograms/l, but an improved version of the test would be useful.

The effect of the lipid peroxidation product 4-hydroxynonenal and of its metabolite 4-hydroxynonenoic acid on respiration of rat kidney cortex mitochondria

In rat kidney cortex mitochondria, 4-hydroxynonenal inhibits state 3 respiration as well as uncoupled respiration at micromolar concentrations. The inhibition is more distinct for NAD-linked than for FAD-linked respiration. 4-Hydroxynonenal increases the state 4 respiration. It is assumed that 4-hydroxynonenal behaves like a decoupling agent. 4-Hydroxynonenal augments the inhibitory effect of 2,4-dinitrophenol observed at superoptimal concentrations. 4-Hydroxynonenal is metabolised by renal mitochondria, and 4-hydroxynonenoic acid is one of the metabolites generated. This metabolite is without effect on respiration at concentrations up to 50 microM. Therefore, the effect of 4-hydroxynonenal on respiration is not mediated by this fatty acid derivative formed during respiratory measurements.

Comparison between equimolar- and skewed-response assays of prostate specific antigen: is there an influence on the clinical significance when measuring total serum prostate specific antigen?

Using the Tandem-E, Axsym and LIA-mat assays, prostate specific antigen (PSA) was measured in pure PSA solutions of known concentrations of free and complexed PSA and in serum of patients with prostate cancer (n = 31), benign prostate hyperplasia (n = 32) and in healthy controls (n = 27). Measurements of pure PSA solutions showed that the AxSym assay exemplified typical properties of the skewed-response assay reacting more to free PSA than to the complexed PSA forms whereas the other two assays showed an equimolar-response. When PSA was measured in the serum of the tree groups, the AxSym test and Tandem-E gave similar PSA values whereas the LIA-mat test yielded significantly lower values. These results were not related to the amount of free PSA in the samples and proved that discordant PSA values between PSA assays were not mainly caused by the use of skewed- or equimolar assays. Despite these differences, receiver-operation characteristic analysis confirmed that the clinical validity of all three PSA tests did not differ.

Soluble CD44 molecules in serum of patients with prostate cancer and benign prostatic hyperplasia

Recent studies suggest that expression of CD44 splice variants are of prognostic significance for a variety of neoplasias. It was the aim of this study to investigate whether any correlation exists between the concentration of soluble CD44 molecules in serum (CD44 standard form and CD44 splice variants v5 and v6) and the prostate cancer stage. Serum levels of these soluble CD44 isoforms were measured by ELISA tests specific for these proteins in controls (n = 30), patients with benign prostatic hyperplasia (BPH; n = 30), with prostate cancer without metastasis (T1,2,3pN0M0; n = 30) and with locally advanced prostate cancer and/or metastatic disease (T3,4pN1,2M1; n = 19). sCD44std and sCD44v6 concentrations were not significantly different among the four groups studied, with few patients' levels outside the central 95% reference intervals. The mean sCD44v5 concentrations of both prostate cancer and BPH patients were significantly lower than those of the controls. There was no significant difference between the soluble CD44 concentrations of the two groups of prostate cancer patients studied. In contrast to results observed in other carcinomas, the determination of soluble CD44 proteins in serum is not suitable for providing additional prognostic information on patients with prostate cancer.

Developmental changes of antioxidant enzymes in kidney and liver from rats

The five principal antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase in the kidney and liver, and the total hepatic glutathione were determined in rats of different ages (1, 2, 3, 6, and 12 months). Variance analysis proved the effect of age on the measured enzymes in the respective organ with the exception of glutathione S-transferase. The behavior of the enzymes was not uniform, and there were both increased and decreased changes in the two organs. A clear correlation between cellular antioxidative capacity and the age-specific processes of growing or aging could not be seen. A far more complicated network of interactions has to be assumed.

Effects of preservation solutions on cortical and medullary mitochondria of rat kidney

The mitochondria isolated from cortex and medulla of rat kidneys were examined after storage in either Euro-Collins solution, in Bretschneider's histidine-tryptophan-ketoglutarat solution or in Belzer's University of Wisconsin solution at 25 degrees C or at 4 degrees C for a maximum of 4 to 24 hrs. Independently to the preservation of the solution used, the storage of the kidneys led to a decrease in state 3 respiration and uncoupled respiration as well as to an increase in the rate of state 4 respiration. The decrease in state 3 respiration ran parallelly to a decrease in adenine nucleotides. For the homogeneous protection of the mitochondria as well from the cortex as from the medulla, the Bretschneider's solution had the best preservative effect at a storage temperature of 25 degrees C as shown by the measured mitochondrial parameters. At 4 degrees C storage temperature, the differences in action with the various examined solutions were markedly smaller. However, compared to the other two solutions, the Euro-Collins solution showed a more favourable protective effect on cortical and medullary mitochondria.

Identification of metabolic pathways of the lipid peroxidation product 4-hydroxynonenal by mitochondria isolated from rat kidney cortex

The cytosolic lipid peroxidation product 4-hydroxynonenal (HNE) is rapidly metabolized in mitochondria isolated from rat kidney cortex. About 80% of HNE was degraded within 3 min of incubation. Main products of HNE which were identified in mitochondria were the hydroxynonenoic acid, the 1,4-dihydroxynonene and the glutathione-HNE-conjugate. Furthermore, formation of metabolites of the tricarboxylic acid cycle from HNE is suggested. The quantitative share of HNE binding to proteins was high with about 8% of total HNE consumption after 3 min of incubation. Therefore, rapid degradation of HNE by mitochondria might be involved in an intracellular antioxidative defense system.