Loss of the novel Vcp (valosin containing protein) interactor Washc4 interferes with autophagy-mediated proteostasis in striated muscle and leads to myopathy in vivo

VCP/p97 (valosin containing protein) is a key regulator of cellular proteostasis. It orchestrates protein turnover and quality control in vivo, processes fundamental for proper cell function. In humans, mutations in VCP lead to severe myo- and neuro-degenerative disorders such as inclusion body myopathy with Paget disease of the bone and frontotemporal dementia (IBMPFD), amyotrophic lateral sclerosis (ALS) or and hereditary spastic paraplegia (HSP). We analyzed here the in vivo role of Vcp and its novel interactor Washc4/Swip (WASH complex subunit 4) in the vertebrate model zebrafish (Danio rerio). We found that targeted inactivation of either Vcp or Washc4, led to progressive impairment of cardiac and skeletal muscle function, structure and cytoarchitecture without interfering with the differentiation of both organ systems. Notably, loss of Vcp resulted in compromised protein degradation via the proteasome and the macroautophagy/autophagy machinery, whereas Washc4 deficiency did not affect the function of the ubiquitin-proteasome system (UPS) but caused ER stress and interfered with autophagy function in vivo. In summary, our findings provide novel insights into the in vivo functions of Vcp and its novel interactor Washc4 and their particular and distinct roles during proteostasis in striated muscle cells.

The cell polarity proteins Boi1p and Boi2p stimulate vesicle fusion at the plasma membrane of yeast cells

Eukaryotic cells can direct secretion to defined regions of their plasma membrane. These regions are distinguished by an elaborate architecture of proteins and lipids that are specialized to capture and fuse post-Golgi vesicles. Here we show that the proteins Boi1p and Boi2p are important elements of this area of active exocytosis at the tip of growing yeast cells. Cells lacking Boi1p and Boi2p accumulate secretory vesicles in their bud. The essential PH domains of Boi1p and Boi2p interact with Sec1p, a protein required for SNARE complex formation and vesicle fusion. Sec1p loses its tip localization in cells depleted of Boi1p and Boi2p but can partially compensate for their loss upon overexpression. The capacity to simultaneously bind phospholipids, Sec1p, multiple subunits of the exocyst, Cdc42p, and the module for generating active Cdc42p identify Boi1p and Boi2p as essential mediators between exocytosis and polar growth.

[Analgesia with intra-articular morphine following knee joint arthroscopy? A double-blind, randomized study with patient-controlled analgesia]

Previous studies investigating the peripheral action of locally instilled morphine after arthroscopic knee surgery found evidence for an analgesic effect. Follow-up studies have lead to conflicting results. We used patient-controlled analgesia (PCA) to test the analgesic potency of intraarticular morphine. METHODS. Patients undergoing arthroscopic knee surgery under general anaesthesia received, after written informed consent and in double-blind and randomised manner, 1 mg morphine diluted in 10 ml saline either intraarticularly or intravenously at the end of the surgical procedure. A control injection of 10 ml saline was given at the other site. The pain intensity on a visual analogue scale (VAS) and the cumulative morphine consumption were recorded at 1, 2, 3, 4, 6, 8 and 24 h after the end of general anaesthesia.

STATISTICS

Wilcoxon rank sum test with P < 0.05. RESULTS. A total of 59 patients were included in the study; 29 received morphine intraarticularly (verum group), 30 intravenously (control group). There was no difference in gender, age, duration of arthroscopy or anaesthesia. There were more than 60% diagnostic arthroscopies in both groups; other types of surgery were comparable, with the exception of cruciate band repair procedures only in the control group. We found no difference in morphine consumption or pain intensity between the two groups throughout the study period. Median overall consumption of morphine after 24 h was 14 mg in the verum group and 15 mg in the control group, with wide interindividual variation. Pain intensities were remarkably low. The peak pain intensity of both groups was found at 1 h postoperatively, with median 16/100 on the VAS in both groups. Blinding was robust. CONCLUSION. We found no reduction in postoperative morphine supplementation after 1 mg morphine intraarticularly compared to 1 mg intravenously given at the end of knee arthroscopies. There were also no differences in pain intensities on a VAS. We conclude that titration of postoperative pain with a morphine-filled PCA pump was unable to show a difference in analgesic potency between intraarticular and intravenous morphine.

[Axillary blockade of the brachial plexus. A prospective study of blockade success using electric nerve stimulation]

Axillary block is a common anesthetic technique for operations on the hand and forearm. In our hospital, with many trainees in anaesthesia, only 250-300 axillary blocks per year are performed by about 30 colleagues. This implies a small number of blocks for each anaesthetist. The present study was designed to assess whether it is possible to teach this technique and use it with an adequate degree of success under these conditions. We used a nerve stimulator and studied whether the success of the block under these conditions is independent of anaesthetist's experience in this technique. Furthermore, we examined other factors involved in the success of the block. METHODS. The study included 112 patients subjected to elective surgery of the upper extremity; all received an axillary block. We used a nerve stimulator and injected mepivacaine 1% without adrenaline. The following parameters were recorded: the number of blocks to date performed by the anaesthetist; the minimal current required for nerve stimulation; the dose of local anaesthetic; the time between the end of injection and the beginning of surgery; the quality of sensory and motor blockade after 10, 20, and 30 min. Sensory blockade was assessed by the pinprick method (no blockade, analgesia, anaesthesia); motor blockade was judged by comparing the muscle strength of both arms (no blockade, paresis, paralysis). Data were analyzed using the Mann-Whitney test, with P < 0.05 considered statistically significant. RESULTS. Of the 112 blocks, 95 (85%) were successful; 17 (15%) failed and the patients required general anaesthesia. Eight of the successful blocks showed a decrease in analgesic quality after > or = 70 min and required additional analgesics or general anaesthesia. We found no correlation between the experience of the anaesthetist and the success of the block. The minimal required current for nerve stimulation in the success group was 0.4 mA and differed significantly from the value of 0.6 mA in the failure group (Table 3). The dose of mepivacaine was higher in the success group (5.9 vs. 5.3 mg/kg). Complete sensory blockade was more frequently achieved for the median, ulnar, and radial nerves than for the musculocutaneus and cutaneous brachii medialis (Fig. 3). The frequency of complete sensory blockade (anaesthesia) had increased by 21.9% between the 20th and 30th min. Complete motor blockade was less often achieved than sensory blockade (Fig. 4). CONCLUSIONS. Using the method of electrostimulation, the axillary block is an appropriate anaesthetic technique that can be applied in a hospital where each anaesthetist only occasionally performs it. Prior to injection of the local anaesthetic, the current for nerve stimulation should be reduced to < 0.5 mA. The time between the end of injection and the beginning of surgery should be no less than 30 min because complete sensory blockade can more often be achieved. The dose of mepivacaine should be no less than 6 mg/kg body weight.

[Postoperative peridural analgesia via catheter following abdominal surgery. Peridural bupivacaine versus buprenorphine]

Seventy-five patients scheduled for major abdominal operations were randomly divided into four groups, each with a different postoperative analgesic regime. Group I: buprenorphine 4 micrograms/kg was injected i.v. every 4 h. Groups II-IV: all patients were preoperatively supplied with a thoracic epidural catheter that, however, was not used during the operation. Group II: bupivacaine 0.15 ml/kg was injected epidurally every 2 h, the first dose being 0.5%, the top-ups 0.25%. Group III: buprenorphine 4 micrograms/kg in 10 ml saline was given via the catheter and repeated on request. Group IV: these patients received a combined regime. Bupivacaine was injected as in group II, and in addition buprenorphine was added epidurally in the doses and time intervals of group I. After extubation the patients categorized the intensity of postoperative pain twice, first while lying immobile and then after coughing vigorously, using a rating scale with pain scores from 0 to 10. Thereafter, the analgesic regime described above commenced. One hour later the patients' pain scores were again determined. In addition to pain scores, heart rate (HR), mean arterial pressure (MAP) and paCO2 were recorded at the same points in time. The investigation was then interrupted overnight. The analgesic regime continued as described for groups I and II. Patients in group III received 0.15 mg buprenorphine on request i.v., and in group IV bupivacaine was given as in group II with no further buprenorphine. The study recommenced the next morning at 7:00 a.m. After the initial values (pain scores, HR, MAP, paCO2) had been recorded the analgesic program, as scheduled for each patient, restarted. In group IV buprenorphine was again added to bupivacaine and repeated every 4 h, whereas bupivacaine was injected every 2 h. All values were registered hourly until 7:00 p.m., when the investigation was terminated. RESULTS. On the day of operation and during the first few hours on the morning thereafter, analgesia in groups II and IV was considerably better compared to groups I and III (P less than 0.001). We could not statistically demonstrate, however, that analgesia in group IV was superior to that in group II despite the fact that pain scores were lowest in this group, with a median at rest of 0 throughout the study time. In group III (n = 20), epidural buprenorphine failed to produce any acceptable analgesic effect in 6 patients despite correct catheter position. For this reason they were dropped from the study. No patient in any of the other groups, however, was dropped (P less than 0.01). Later in the 1st postoperative day analgesia in groups II and IV lost its superiority at rest, but coughing continued to be less painful in comparison to groups I and III. We noticed that the duration of action of 0.25% bupivacaine, injected as a bolus, was considerably shorter than expected (less than 2 h) and that several patients experienced pain before the next top-up was given...