Sickle cell disease in mice is associated with sensitization of sensory nerve fibers

The pain phenotype in sickle cell disease (SCD) patients is highly variable. A small percentage of SCD patients experience many vaso-occlusive crises/year, 5% of patients account for over 30% of pain episodes, while 39% report few episodes of severe pain. Clearly, a better understanding of the pathobiology of SCD is needed to improve its therapy. Humanized sickle cell mice recapitulate several phenotypes of SCD patients and provide a model for the study of SCD pain. Researchers have shown that one strain of humanized SCD mice, the BERK strain, has abnormal pain phenotype. However, the nociception phenotype of another humanized SCD mouse strain, the Townes strain, has not been described. In a large cross-sectional study of BERK and Townes SCD mice, we examined thermosensory response and sensory nerve fiber function using sine-wave electrical stimulation at 2000, 250, and 5 Hz to stimulate preferentially Aβ, Aδ, and C sensory nerve fibers, respectively. We found that BERK and Townes mice, compared to respective controls, had decreases in 2000, 250, and 5 Hz current vocalization thresholds in patterns that suggest sensitization of a broad spectrum of sensory nerve fibers. In addition, the pattern of sensitization of sensory fibers varied according to strain, sex, age, and mouse genotype. In a similarly variable pattern, Townes and BERKs also had significantly altered sensitivity to noxious thermal stimuli in agreement with what has been shown by others. In summary, the analysis of somatosensory function using sine-wave electrical stimulation in humanized sickle cell mice suggests that in SCD, both myelinated and unmyelinated, fibers are sensitized. The pattern of sensory fiber sensitization is distinct from that observed in pain models of neuropathic and inflammatory pain. These findings raise the possibility that sensitization of a broad spectrum of sensory fibers might contribute to the altered and variable nociception phenotype in SCD.     

Mitochondrial DNA content and mass increase in progression from normal to hyperplastic to cancer endometrium

ABSTRACT: BACKGROUND: An increase in mitochondrial DNA (mtDNA) content and mitochondrial biogenesis associated with the activation of PGC-1alpha signalling pathway was previously reported in type I endometrial cancer. The aim of this study has been to evaluate if mtDNA content and the citrate synthase (CS) activity, an enzyme marker of mitochondrial mass, increase in progression from control endometrium to hyperplasia to type I endometrial carcinoma. RESULTS: Given that no statistically significant change in mtDNA content and CS activity in endometrium taken from different phases of the menstrual cycle or in menopause was found, these samples were used as control. Our research shows, for the first time, that mtDNA content and citrate synthase activity increase in hyperplastic endometrium compared to control tissues, even if their levels remain lower compared to cancer tissue. In particular, mtDNA content increases seem to precede increases in CS activity. No statistically significant change in mtDNA content and in CS activity was found in relation to different histopathological conditions such as grade, myometrial invasion and stage. CONCLUSION: MtDNA content and citrate synthase activity increases in pre-malignant lesions could be a potential molecular marker for progression from hyperplasia to carcinoma.     

Stably expressed <Emphasis Type="SmallCaps">d</Emphasis>-genome-derived HMW glutenin subunit genes transformed into different durum wheat genotypes change dough mixing properties

Durum wheat (Triticum turgidum L. var. durum) is traditionally used for the production of numerous types of pasta, and significant amounts are also used for bread-making, particularly in southern Italy. The research reported here centres on the glutenin subunits 1Dx5 and 1Dy10 encoded by chromosome 1D, and whose presence in hexaploid wheats is positively correlated with higher dough strength. In order to study the effects of stable expression of the 1Dx5 and 1Dy10 glutenin subunits in different durum wheat genotypes, four cultivars commonly grown in the Mediterranean area (‘Svevo’, ‘Creso’, ‘Varano’ and ‘Latino’) were co-transformed, via particle bombardment of cultured immature embryos, with the two wheat genes Glu-D1-1d and Glu-D1-2b encoding the glutenin subunits, and a third plasmid containing the bar gene as a selectable marker. Protein gel analyses of T₁ generation seed extracts showed expression of one or both glutenin genes in four different transformed durum wheat plants. One of these transgenic lines, DC2-65, showed co-suppression of all HMW-GS, including the endogenous ones. Transgene stability in the transgenic lines has been studied over four generations (T₁–T₄). Fluorescence in situ hybridization (FISH) analysis of metaphase chromosomes from T₄ plants showed that the integration of transgenes occurred in both telomeric and centromeric regions. The three plasmids were found inserted at a single locus in two lines and in two loci on the same chromosome arm in one line. The fourth line had two transgenic loci on different chromosomes: one with both glutenin plasmids and a different one containing only the construct with the gene encoding the 1Dy10 glutenin subunit. Segregation of these two loci in subsequent generations allowed establishment of two sublines, one containing both 1Dx5 and 1Dy10 and the other containing only 1Dy10. Small-scale quality tests showed that accumulation of Dx5, Dy10 or both in transgenic durum wheat seeds resulted in doughs with stronger mixing characteristics. A. Gadaleta and A. E. Blechl have contributed equally to this work.     

Production of reactive species and modulation of antioxidant network in response to heat shock: a critical balance for cell fate

Exposure to adverse temperature conditions is a common stress factor for plants. In order to cope with heat stress, plants activate several defence mechanisms responsible for the control of reactive oxygen species (ROS) and redox homeostasis. Specific heat shocks (HSs) are also able to activate programmed cell death (PCD). In this paper, the alteration of several oxidative markers and ROS scavenging enzymes were studied after subjecting cells to two different HSs. Our results suggest that, under moderate HS, the redox homeostasis is mainly guaranteed by an increase in glutathione (GSH) content and in the ascorbate peroxidase (APX) and catalase (CAT) activities. These two enzymes undergo different regulatory mechanisms. On the other hand, the HS-induced PCD determines an increase in the activity of the enzymes recycling the ascorbate- and GSH-oxidized forms and a reduction of APX; whereas, CAT decreases only after a transient rise of its activity, which occurs in spite of the decrease of its gene expression. These results suggest that the enzyme-dependent ROS scavenging is enhanced under moderate HS and suppressed under HS-induced PCD. Moreover, the APX suppression occurring very early during PCD, could represent a hallmark of cells that have activated a suicide programme.     

Mitochondrial DNA, RNA and protein synthesis in normal and hypothyroid developing rat liver

Mitochondrial DNA, RNA and protein synthesis in normal and hypothyroid rat liver between the ages of -3 and 21 days were followed. In normal rats DNA polymerase activity and protein synthesis behaved similarly, showing two peaks of activity, one at -3 and the other at 21 days of age. RNA polymerase activity did not change between days -3 and 14, whereas it increased by 21 days of age. Hypothyroidism delayed the developmental pattern of DNA polymerase activity, affected RNA polymerase activity only at 21 days, whereas it inhibited protein synthesis at birth and in the third week of life. The cytochrome aa3 content appeared to be affected by hypothyroidism at birth and at 21 days of age.