Modulation of PARP-1 Activity in a Broad Time Window Attenuates Memorizing Fear.

The amygdala plays a critical role in the acquisition and consolidation of fear-related memories. Recent studies have demonstrated that ADP-ribosylation of histones, accelerated by PARPs, affects the chromatin structure and the binding of chromatin remodeling complexes with transcription factors. Inhibition of PARP-1 activity during the labile phase of re-consolidation may erase memory. Accordingly, we investigated the possibility of interfering with fear conditioning by PARP-1 inhibition. Herein, we demonstrate that injection of PARP-1 inhibitors, specifically into the CeA or i.p., in different time windows post-retrieval, attenuates freezing behavior. Moreover, the association of memory with pharmacokinetic timing of PARP inhibitor arrival to the brain enabled/achieved attenuation of a specific cue-associated memory of fear but did not hinder other memories (even traumatic events) associated with other cues. Our results suggest using PARP-1 inhibitors as a new avenue for future treatment of PTSD by disrupting specific traumatic memories in a broad time window, even long after the traumatic event. The safety of using these PARP inhibitors, that is, not interfering with other natural memories, is an added value.

Ultrasound targeting of Q-starch/miR-197 complexes for topical treatment of psoriasis.

Psoriasis is a common, worldwide autoinflammatory, incurable skin disease. miR-197 has therapeutic potential for psoriasis since it can down-regulate the expression of both IL-22RA1 and IL-17RA, subunits of the receptors of IL-22 and IL-17, respectively, which are key cytokines in the disease. Although miR-197 has the potential to treat the disease, several inherent physical barrier properties of the skin challenge miRNA's delivery to the target skin cells. In the present study, we evaluated a therapeutic approach that combines the use of ultrasound (US) as a means to enhance skin permeability with quaternized starch (Q-starch) as an miRNA delivery carrier. This resulted in decreased expression of the miR-197 target proteins and in a significant reduction in the psoriatic activity markers. Our results demonstrate the potential of combinations of US and Q-starch/miR-197 complexes for the topical skin treatment of psoriasis.

Overexpression of corticotropin-releasing factor receptor type 2 in the bed nucleus of stria terminalis improves posttraumatic stress disorder-like symptoms in a model of incubation of fear.

BACKGROUND: Posttraumatic stress disorder (PTSD) is a severe, persistent psychiatric disorder in response to a traumatic event, causing intense anxiety and fear. These responses may increase over time upon conditioning with fear-associated cues, a phenomenon termed fear incubation. Corticotropin-releasing factor receptor type 1 (CRFR1) is involved in activation of the central stress response, while corticotropin-releasing factor receptor type 2 (CRFR2) has been suggested to mediate termination of this response. Corticotropin-releasing factor (CRF) receptors are found in stress-related regions, including the bed nucleus of stria terminalis (BNST), which is implicated in sustained fear. METHODS: Fear-related behaviors were analyzed in rats exposed to predator-associated cues, a model of psychological trauma, over 10 weeks. Rats were classified as susceptible (PTSD-like) or resilient. Expression levels of CRF receptors were measured in the amygdala nuclei and BNST of the two groups. In addition, lentiviruses overexpressing CRFR2 were injected into the medial division, posterointermediate part of the BNST (BSTMPI) of susceptible and resilient rats and response to stress cues was measured. RESULTS: We found that exposure to stress and stress-associated cues induced a progressive increase in fear response of susceptible rats. The behavioral manifestations of these rats were correlated both with sustained elevation in CRFR1 expression and long-term downregulation in CRFR2 expression in the BSTMPI. Intra-BSTMPI injection of CRFR2 overexpressing lentiviruses attenuated behavioral impairments of susceptible rats. CONCLUSIONS: These results implicate the BNST CRF receptors in the mechanism of coping with stress. Our findings suggest increase of CRFR2 levels as a new approach for understanding stress-related atypical psychiatric syndromes such as PTSD.

ß-endorphin via the delta opioid receptor is a major factor in the incubation of cocaine craving.

Cue-induced cocaine craving intensifies, or 'incubates', during the first few weeks of abstinence and persists over extended periods of time. One important factor implicated in cocaine addiction is the endogenous opioid ß-endorphin. In the present study, we examined the possible involvement of ß-endorphin in the incubation of cocaine craving. Rats were trained to self-administer cocaine (0.75 mg/kg, 10 days, 6 h/day), followed by either a 1-day or a 30-day period of forced abstinence. Subsequent testing for cue-induced cocaine-seeking behavior (without cocaine reinforcement) was performed. Rats exposed to the drug-associated cue on day 1 of forced abstinence demonstrated minimal cue-induced cocaine-seeking behavior concurrently with a significant increase in ß-endorphin release in the nucleus accumbens (NAc). Conversely, exposure to the cue on day 30 increased cocaine seeking, while ß-endorphin levels remained unchanged. Intra-NAc infusion of an anti-ß-endorphin antibody (4 µg) on day 1 increased cue-induced cocaine seeking, whereas infusion of a synthetic ß-endorphin peptide (100 ng) on day 30 significantly decreased cue response. Both intra-NAc infusions of the δ opioid receptor antagonist naltrindole (1 µg) on day 1 and naltrindole together with ß-endorphin on day 30 increased cue-induced cocaine-seeking behavior. Intra-NAc infusion of the µ opioid receptor antagonist CTAP (30 ng and 3 µg) had no behavioral effect. Altogether, these results demonstrate a novel role for ß-endorphin and the δ opioid receptor in the development of the incubation of cocaine craving.

The upstream open reading frame of the Arabidopsis AtMHX gene has a strong impact on transcript accumulation through the nonsense-mediated mRNA decay pathway.

Approximately 20% of plant genes possess upstream open-reading frames (uORFs). The effect of uORFs on gene expression has mainly been studied at the translational level. Very little is known about the impact of plant uORFs on transcript content through the nonsense-mediated mRNA decay (NMD) pathway, which degrades transcripts bearing premature termination codons (PTCs). Here we examine the impact of the uORF of the Arabidopsis AtMHX gene on transcript accumulation. The suggestion that this uORF exposes transcripts containing it to NMD is supported by (i) the increase in transcript levels upon eliminating the uORF from constructs containing it, (ii) experiments with a modified uORF-peptide, which excluded peptide-specific degradation mechanisms, (iii) the increase in levels of the native AtMHX transcript upon treatment with cycloheximide, which inhibits translation and blocks NMD, and (iv) the sensitivity of transcripts containing the uORF of AtMHX to the presence of introns. We also showed that introns can increase NMD efficiency not only in transcripts having relatively short 3' untranslated regions (UTRs), but also in uORF-containing transcripts. AtMHX transcript levels were almost unaltered in mutants of the NMD factors UPF3 and UPF1. Possible reasons, including the existence of a NMD-compensatory mechanism, are discussed. Interestingly, the levels of UPF3 transcript were higher in upf1 mutants, suggesting a compensatory mechanism that links weak function of the NMD machinery to increased expression of UPF3. Our findings highlight that uORFs, which are abundant in plants, can not only inhibit translation but also strongly affect transcript accumulation.