Immune activation and target organ damage are consequences of hydrodynamic treatment but not delivery of naked siRNAs in mice

Short-interfering RNAs (siRNAs), key mediators of RNA interference comprise a promising therapeutic tool, although side effects such as interferon (IFN) response are still not perfectly understood. Further, delivery to target organs is a major challenge, possibly associated with side effects including immune activation or organ damage. We investigated whether immune activation as a consequence of double-stranded RNA induced IFN response (Jak/STAT pathway activation or cytokine production) or target organ damage is induced by in vivo low-volume (LV) or high-volume (HV) hydrodynamic delivery or treatment with naked siRNA. NMRI mice were injected with naked siRNAs or saline by hydrodynamic injection (HDI) and positive control mice received polyinosinic-polycytidilic acid (poly I:C). LV (1?mL/mouse) and HV (10% of body weight) HDI were compared. After LV HDI, STAT1 and OAS1 gene expression inflammatory cytokine plasma levels and target organ injury were assessed. LV HDI induced slight alanine aminotransferase elevation and mild hepatocyte injury, whereas HV HDI resulted in high ALAT level and extensive hepatocyte necrosis. STAT1 or OAS1 was not induced by LV siRNA; however, HV saline led to a time-dependent slight increase in gene expression. Inflammatory cytokine plasma level and organ histology and functional parameters demonstrated no damage following LV HDI with or without siRNA. Our data demonstrate that naked siRNAs may be harnessed, without the induction of IFN response or immune activation, and that LV HDI is preferable, because HV HDI may cause organ damage.     

Theoretical calculations on hydrogenase kinetics: explanation of the lag phase and the enzyme concentration dependence of the activity of hydrogenase uptake

Two models of the hydrogenase reaction cycle were investigated by means of theoretical calculations and model simulations. The first model is the widely accepted triangular hydrogenase reaction cycle with minor modifications; the second is a modified triangular model, where we have introduced an autocatalytic step into the reaction cycle. Both models include a one-step activation reaction. The theoretical calculations and model simulations corroborate the assumed autocatalytic reaction step concluded from the experimental characteristics of the hydrogenase reaction.     

Gene expression profiling in murine autoimmune arthritis during the initiation and progression of joint inflammation

We present here an extensive study of differential gene expression in the initiation, acute and chronic phases of murine autoimmune arthritis with the use of high-density oligonucleotide arrays interrogating the entire mouse genome. Arthritis was induced in severe combined immunodeficient mice by using adoptive transfer of lymphocytes from proteoglycan-immunized arthritic BALB/c mice. In this unique system only proteoglycan-specific lymphocytes are transferred from arthritic mice into syngeneic immunodeficient recipients that lack adaptive immunity but have intact innate immunity on an identical (BALB/c) genetic background.     

Fission yeast homologue of Tip41-like proteins regulates type 2A phosphatases and responses to nitrogen sources

A fission yeast (Schizosaccharomyces pombe) gene encoding a member of the TIP41-like protein family was identified and characterized. Deletion of the fission yeast tip41 gene leads to slower growth when ammonium chloride is the nitrogen source, but the growth rate is not affected when adenine is the nitrogen source. The tip41 mutant cells also enter the G1 phase of the cell cycle earlier than wild-type cells in response to nitrogen starvation. Overexpression of tip41(+) causes cell death, spherical cell morphology and blocks the shift to G1 phase upon nitrogen starvation. Overexpression of tip41(+) increases the activity of type 2A phosphatase. In a ppa2 deletion strain with reduced PP2A activity, overexpression of tip41(+) no longer blocks the shift to G1 upon nitrogen starvation. These results suggest that fission yeast Tip41 plays a role in cellular responses to nitrogen nutrient conditions at least partly through regulation of type 2A phosphatase activity.     

Altered elementary calcium release events and enhanced calcium release by thymol in rat skeletal muscle

The effects of thymol on steps of excitation-contraction coupling were studied on fast-twitch muscles of rodents. Thymol was found to increase the depolarization-induced release of calcium from the sarcoplasmic reticulum, which could not be attributed to a decreased calcium-dependent inactivation of calcium release channels/ryanodine receptors or altered intramembrane charge movement, but rather to a more efficient coupling of depolarization to channel opening. Thymol increased ryanodine binding to heavy sarcoplasmic reticulum vesicles, with a half-activating concentration of 144 micro M and a Hill coefficient of 1.89, and the open probability of the isolated and reconstituted ryanodine receptors, from 0.09 +/- 0.03 to 0.22 +/- 0.04 at 30 micro M. At higher concentrations the drug induced long-lasting open events on a full conducting state. Elementary calcium release events imaged using laser scanning confocal microscopy in the line-scan mode were reduced in size, 0.92 +/- 0.01 vs. 0.70 +/- 0.01, but increased in duration, 56 +/- 1 vs. 79 +/- 1 ms, by 30 micro M thymol, with an increase in the relative proportion of lone embers. Higher concentrations favored long events, resembling embers in control, with duration often exceeding 500 ms. These findings provide direct experimental evidence that the opening of a single release channel will generate an ember, rather than a spark, in mammalian skeletal muscle.     

Single neonatal treatment with beta-endorphin (hormonal imprinting) extremely enhances nocistatin level of cerebrospinal fluid in adult rats

In earlier experiments endorphin treatment of newborn rats caused the decrease of brain serotonin content, increasing aggressivity, enhanced sexual activity of females and changes in the binding capacity of uterine estrogen receptors at adult age, however nociceptin content of the cerebrospinal fluid was not changed. In the present experiment neonatal treatment of male and female rats was done with a single dose of 3 microg beta-endorphin and in five months old rats the level of nociceptin antagonist nocistatin was determined by radioimmunoassay in the cerebrospinal fluid. In both genders the amount of nocistatin was one magnitude higher in the endorphin treated groups. There was also a significant difference between the male and female nocistatin level in the treated and non-treated groups alike, with the advantage of females. The results call attention to the possibility of influencing pain-tolerance for life, by the pain-provoked endorphin levels during delivery.     

Changing climate in Hungary and trends in the annual number of heat stress days

Global climate change can have serious direct effects on animal health and production through heat stress. In Hungary, the number of heat stress days per year (YNHD), i.e., days when the temperature humidity index (THI) is above a specific comfort threshold, has increased in recent years based on observed meteorological data. Between 1973 and 2008, the countrywide average increase in YNHD was 4.1% per year. Climate scenarios based on regional climate models (RCM) were used to predict possible changes in YNHD for the near future (2021–2050) relative to the reference period (1961–1990). This comparison shows that, in Hungary, the 30-year mean of YNHD is expected to increase by between 1 and 27 days, depending on the RCM used. Half of the scenarios investigated in this study predicted that, in large parts of Hungary, YNHD will increase by at least 1 week. However, the increase observed in the past, and that predicted for the near future, is spatially heterogeneous, and areas that currently have large cattle populations are expected to be affected more severely than other regions.