AKAP150-anchored PKA regulation of synaptic transmission and plasticity, neuronal excitability and CRF neuromodulation in the lateral habenula

Numerous studies of hippocampal synaptic function in learning and memory have established the functional significance of the scaffolding A-kinase anchoring protein 150 (AKAP150) in kinase and phosphatase regulation of synaptic receptor and ion channel trafficking/function and hence synaptic transmission/plasticity, and neuronal excitability. Emerging evidence also suggests that AKAP150 signaling may play a critical role in brain's processing of rewarding/aversive experiences. Here we focused on an unexplored role of AKAP150 in the lateral habenula (LHb), a diencephalic brain region that integrates and relays negative reward signals from forebrain striatal and limbic structures to midbrain monoaminergic centers. LHb aberrant activity (specifically hyperactivity) is also linked to depression. Using whole cell patch clamp recordings in LHb of male wildtype (WT) and ΔPKA knockin mice (with deficiency in AKAP-anchoring of PKA), we found that the genetic disruption of PKA anchoring to AKAP150 significantly reduced AMPA receptor (AMPAR)-mediated glutamatergic transmission and prevented the induction of presynaptic endocannabinoid (eCB)-mediated long-term depression (LTD) in LHb neurons. Moreover, ΔPKA mutation potentiated GABAA receptor (GABAAR)-mediated inhibitory transmission postsynaptically while increasing LHb intrinsic neuronal excitability through suppression of medium afterhyperpolarizations (mAHPs). Given that LHb is a highly stress-responsive brain region, we further tested the effects of corticotropin releasing factor (CRF) stress neuromodulator on synaptic transmission and intrinsic excitability of LHb neurons in WT and ΔPKA mice. As in our earlier study in rat LHb, CRF significantly suppressed GABAergic transmission onto LHb neurons and increased intrinsic excitability by diminishing small-conductance potassium (SK) channel-mediated mAHPs. ΔPKA mutation-induced suppression of mAHPs also blunted the synaptic and neuroexcitatory actions of CRF in mouse LHb. Altogether, our data suggest that AKAP150 complex signaling plays a critical role in regulation of AMPAR and GABAAR synaptic strength, glutamatergic plasticity and CRF neuromodulation possibly through AMPAR and potassium channel trafficking and eCB signaling within the LHb.

Transcriptional repression of PTEN in neural cells using CRISPR/dCas9 epigenetic editing

After damage to the adult mammalian central nervous system (CNS), surviving neurons have limited capacity to regenerate and restore functional connectivity. Conditional genetic deletion of PTEN results in robust CNS axon regrowth, while PTEN repression with short hairpin RNA (shRNA) improves regeneration but to a lesser extent, likely due to suboptimal PTEN mRNA knockdown using this approach. Here we employed the CRISPR/dCas9 system to repress PTEN transcription in neural cells. We targeted the PTEN proximal promoter and 5' untranslated region with dCas9 fused to the repressor protein Krüppel-associated box (KRAB). dCas9-KRAB delivered in a lentiviral vector with one CRISPR guide RNA (gRNA) achieved potent and specific PTEN repression in human cell line models and neural cells derived from human iPSCs, and induced histone (H)3 methylation and deacetylation at the PTEN promoter. The dCas9-KRAB system outperformed a combination of four shRNAs targeting the PTEN transcript, a construct previously used in CNS injury models. The CRISPR system also worked more effectively than shRNAs for Pten repression in rat neural crest-derived PC-12 cells, and enhanced neurite outgrowth after nerve growth factor stimulation. PTEN silencing with CRISPR/dCas9 epigenetic editing may provide a new option for promoting axon regeneration and functional recovery after CNS trauma.

An audit of drug shortages in a community pharmacy practice

BACKGROUND

There are no firm data on drug shortages in Irish community pharmacy. This prospective observational study aimed to characterise the drug shortage problem in an Irish community pharmacy.

AIMS

The primary aim was to determine numbers and durations of drug shortages. Secondary aims included comparing these shortages with Irish Pharmacy Union (IPU) drug shortage lists and determining the frequency with which notifications were received prior to shortages. Further secondary aims were to examine relationships between causes of drug shortages and drug costs and between causes of drug shortages and shortage durations.

METHODS

The study took place in a community pharmacy in a Limerick City suburb between October 2012 and February 2013. Data were collected daily regarding drugs that were dispensed, but unavailable to purchase. Suppliers/manufacturers provided data on the reasons for shortages.

RESULTS

65/1,232 dispensed drugs (5.3%) were in short supply over the study period. Median shortage duration was 13 days (interquartile range 4-32 days) and median cost was <euro>8.10. Numbers of unavailable drugs by month varied from 13 to 38. Monthly IPU drug shortage lists identified between six and eight of these shortages depending on the month. Two notifications were received from suppliers/manufacturers regarding shortages. Parallel exports had the highest mean costs (mean <euro>38.05) and manufacturing problems were associated with the longest durations (mean 57.44 days).

CONCLUSIONS

This study highlights the drug shortage problem in an Irish community pharmacy. We propose that enhanced communication between all stakeholders is the most worthwhile solution. Further studies are needed.

Laparoscopic findings in women with chronic pelvic pain

OBJECTIVE

This study was undertaken to assess the spectrum of pelvic pathology observed at laparoscopy in women with chronic pelvic pain, and to compare women with an identifiable cause of pain to those with no visible pelvic pathology, with regard to symptomatology and demography.

DESIGN

Retrospective case control study reviewing laparoscopy reports and patient records.

SETTING

Department of Obstetrics and Gynaecology, Groote Schuur Hospital.

PATIENTS

One hundred and thirty-six consecutive women undergoing laparoscopic assessment for undiagnosed pelvic pain of at least 6 months' duration, between 1989 and 1991.

MAIN OUTCOME MEASURES

The presence of endometriosis, pelvic adhesions, other pelvic pathology and 'negative' laparoscopic findings was assessed. The association between pelvic pathology and specific symptomatology, fertility, contraceptive use, past pelvic surgery, ethnic group and smoking is examined.

RESULTS

No cause of pain was identified at laparoscopy in 30% of these patients, while endometriosis was found in 16% of women and pelvic adhesions in 40%. The 41 women with no identifiable laparoscopic abnormality did not differ significantly from the 95 with pelvic abnormalities in respect of age, parity, duration of pain, frequency of dysmenorrhoea and dyspareunia or the presence of gastro-intestinal or urinary symptoms. However, injectable hormonal contraception use was more common in the group with negative laparoscopic findings and smoking was more common among the women with pelvic pathology.

CONCLUSION

Chronic pelvic pain with a laparoscopically normal pelvis is a common problem in Cape Town, occurring with a frequency similar to that reported from various overseas centres. Women with this problem are not readily identified by demographic profile or symptom complex.