Pain places a devastating burden on patients and society and current pain therapeutics exhibit limitations in efficacy, unwanted side effects and the potential for drug abuse and diversion. Although ...genetic evidence has clearly demonstrated that the voltage-gated sodium channel, Nav1.7, is critical to pain sensation in mammals, pharmacological inhibitors of Nav1.7 have not yet fully recapitulated the dramatic analgesia observed in Nav1.7-null subjects. Using the tarantula venom-peptide ProTX-II as a scaffold, we engineered a library of over 1500 venom-derived peptides and identified JNJ63955918 as a potent, highly selective, closed-state Nav1.7 blocking peptide. Here we show that JNJ63955918 induces a pharmacological insensitivity to pain that closely recapitulates key features of the Nav1.7-null phenotype seen in mice and humans. Our findings demonstrate that a high degree of selectivity, coupled with a closed-state dependent mechanism of action is required for strong efficacy and indicate that peptides such as JNJ63955918 and other suitably optimized Nav1.7 inhibitors may represent viable non-opioid alternatives for the pharmacological treatment of severe pain.
An overview of pathways encoding nociception Woller, Sarah A; Eddinger, Kelly A; Corr, Maripat ...
Clinical and experimental rheumatology,
01/2017, Letnik:
35 Suppl 107, Številka:
5
Journal Article
Recenzirano
The nervous system detects and interprets a variety of chemical, mechanical, and thermal stimuli. In the face of tissue injury, local inflammatory products perpetuate ongoing activity and ...sensitisation of the peripheral nerve termini. This ongoing activity evokes a state of robust spinal facilitation mediated by a number of local circuits, the net effect yielding an enhanced message of nociception to higher centres. This messaging typically wanes with the resolution of inflammation or wound healing. However, there are situations in which peripheral and central components of the pain transmission pathway extend and enhance the pain state, leading to a persistent hypersensitivity, e.g., an acute to chronic pain transition. Current work points to the contribution of innate and adaptive immunity in creating these enduring conditions. We briefly describe the underlying biological components of both physiological pain processing and pathological pain processing, as well as the acute to chronic pain transition and the role of innate and adaptive immunity in this transition.
Highlights • MBP84-104 peptide, injected into an intact nerve, produces long-lasting pain. • IL-6 is the top-induced cytokine by MBP84-104, regardless of T cell content. • Blockade of spinal IL-6 ...activity reduces MBP84-104-induced pain. • Gabapentin, but not ketorolac, lidocaine or MK801 reverses MBP84-104-induced pain.
Background and aims We systematically characterized the potency and side effect profile of a series of small opioid peptides with high affinity for the mu opioid receptor. Methods Male Sprague Dawley ...rats were prepared with intrathecal (IT) catheters, assessed with hind paw thermal escape and evaluated for side effects including Straub tail, truncal rigidity, and pinnae and corneal reflexes. In these studies, DMT-DALDA (dDAL) (H-Dmt-D-Arg-Phe-Lys-NH2 MW=981), dDALc (H-Dmt-Cit-Phe-Lys-NH2 MW=868), dDALcn (H-Dmt-D-Cit-Phe-Nle-NH2 MW=739), TAPP (H-Tyr-D-Ala-Phe-Phe-NH2 MW=659), dDAL-TICP (Dmt1DALDA-(CH2)2-NH-TICPpsi; MW=1519), and dDAL-TIPP (H-Dmt-D-Arg-Phe-Lys(Nε-TIPP)-NH2 were examined. In separate studies, the effects of approximately equiactive doses of IT DMT DALDA (10 pmol), morphine (30 nmol) and fentanyl (1 nmol) were examined on formalin-induced flinching at different pretreatment intervals (15 min - 24 h). Results (1) All agents resulted in a dose-dependent reversible effect upon motor function (Straub Tail>Truncal rigidity). (2) The ordering of analgesic activity (%MPE) at the highest dose lacking reliable motor signs after bolus delivery was: DMT-DALDA (80%±6/3 pmol); dDALc (75%±8/1 pmol); dDALcn (84%±10/300 pmol); TAPP (56%±12/10 nmol); dDAL-TICP (52%±27/300 pmol). (3) All analgesic effects were reversed by systemic (IP) naloxone (1 mg/kg). Naltrindole (3 mg/kg, IP) had no significant effect upon the maximum usable peptide dose. (4) Tolerance and cross-tolerance development after 5 daily boluses of DMT-DALDA (3 pmol) and morphine (30 nmol) revealed that both agents displayed a progressive decline over 5 days. (5) Cross-tolerance assessed at day 5 revealed a reduction in response to morphine in DMT-DALDA treated animal but not DMT-DALDA in the morphine treated animal, indicating an asymmetric cross-tolerance. (6) IT DMT-DALDA, morphine and fentanyl resulted in significant reductions in phase 1 and phase 2 flinching. With a 15 min pretreatment all drugs resulted in comparable reductions in flinching. However, at 6 h, the reduction in flinching after DMT-DALDA and morphine were comparably reduced while fentanyl was not different from vehicle. All effects on flinching were lost by 24 h. Conclusions These results emphasize the potent mu agonist properties of the DALDA peptidic structure series, their persistence similar to morphine and their propensity to produce tolerance. The asymmetric cross-tolerance between equiactive doses may reflect the relative intrinsic activity of morphine and DMT-DALDA. Implications These results suggest that the DALDA peptides with their potency and duration of action after intrathecal delivery suggest their potential utility for their further development as a spinal therapeutic to manage pain.
Capsules for the National Ignition Facility require measurement of isolated defects on the capsule surface. A phase-shifting diffraction interferometer (PSDI) is used to identify, locate, and measure ...defects by capturing 71 overlapping -500-mum-diam charge coupled device height maps for software analysis. Using capsules with drilled holes for the purpose of alignment, PSDI data were confirmed with atomic force microscopy by comparing defect data from corresponding equatorial bands. We explored the limitations of the PSDI resulting from unwrapping errors caused by defect slopes greater than the Nyquist sampling theorem. White light interferometry proved to be a useful complementary tool to measure defects that could not be unwrapped by the analysis software. Implementing the PSDI in conjunction with the shell flipper, both developed at Lawrence Livermore National Laboratory, allowed for full mapping of shell surfaces by mounting corresponding hemispheres onto the PSDI within a 2-deg accuracy.
An instrumentation of X-ray absorption spectroscopy (XAS) was developed to measure the areal density of any element with an atomic number Z > 17. In contrast to X-ray fluorescence, which is affected ...by spatial dopant nonuniformity, an element can be accurately measured by XAS regardless of its own distribution or the presence of other elements in a sample. Furthermore, no reference standard is needed to achieve ±3% 1Ã accuracy. This method has been used to measure the average contents of specific elements in a variety of inertial confinement fusion and high energy density targets. It validates the average dopant concentration measured by contact radiography and differential radiography.
National Ignition Facility (NIF) specifications require nondestructive, independent profiling of copper, argon, and oxygen in a delivered beryllium capsule. We use a combination of two methods to ...accomplish this goal: (a) model-enhanced energy dispersive spectroscopy (EDS) of witness shell fragments for destructive profiling of all three elements in a select sample within a batch and (b) differential radiography (DR) to profile copper and argon on multiple shells to nondestructively prove the sample-to-sample consistency within a batch. This combination fully qualifies the delivered shells. For EDS, we developed a physics model and fabricated standards to quantify low concentrations of relatively light elements in a very low-Z matrix. For model validation, we produced sputtered beryllium capsules containing a single dopant in each shell and used contact radiography (CR) to characterize the dopant profiles to 5 to 10% accuracy. The copper calibration was also checked against bulk Cu-Be standards with known composition, and the argon and oxygen calibrations were also checked against the X-ray absorption edge spectroscopy (Edge method) and the weight gain methods. Together, the EDS method gives ±0.1, ±0.05, and ±0.2 at.% accuracy for copper, argon, and oxygen, respectively, in NIF specification capsules. For DR, we conduct two CR measurements with the X-ray tube running at 9 and 30 kVp, respectively. The differential response between copper and argon enables elemental separation. The dopant profiles can be measured to ±0.1 at.% for NIF specification capsules. The oxygen profile in DR must be inferred from the EDS measurement. In the production work flow, we use EDS to obtain the oxygen profile and use it as input to the DR measurement. We then check that the copper and argon profiles obtained from DR and those from EDS are consistent. The average argon and copper contents from either method can also be checked against the results from the Edge method. These two levels of cross-checks offer critical assurances to the data integrity in production metrology.
Aberrant tumor necrosis factor-α (TNFα) signaling is associated with many inflammatory diseases. The homotrimeric quaternary structure of TNFα is essential for receptor recognition and signal ...transduction. Previously, we described an engineered α/β-peptide inhibitor that potently suppresses TNFα activity and resists proteolysis. Here, we present structural evidence that both the α/β-peptide inhibitor and an all-α analogue bind to a monomeric form of TNFα. Calorimetry data support a 1:1 inhibitor/TNFα stoichiometry in solution. In contrast, previous cocrystal structures involving peptide or small-molecule inhibitors have shown the antagonists engaging a TNFα dimer. The structural data reveal why our inhibitors favor monomeric TNFα. Previous efforts to block TNFα-induced cell death with peptide inhibitors revealed that surfactant additives to the assay conditions cause a more rapid manifestation of inhibitory activity than is observed in the absence of additives. We attributed this effect to a loose surfactant TNFα association that lowers the barrier to trimer dissociation. Here, we used the new structural data to design peptide inhibitors bearing a surfactant-inspired appendage intended to facilitate TNFα trimer dissociation. The appendage modified the time course of protection from cell death.
In the peripheral nerve, mechanosensitive axons are insulated by myelin, a multilamellar membrane formed by Schwann cells. Here, we offer first evidence that a myelin degradation product induces ...mechanical hypersensitivity and global transcriptomics changes in a sex-specific manner. Focusing on downstream signaling events of the functionally active 84-104 myelin basic protein (MBP(84-104)) fragment released after nerve injury, we demonstrate that exposing the sciatic nerve to MBP(84-104) via endoneurial injection produces robust mechanical hypersensitivity in female, but not in male, mice. RNA-seq and systems biology analysis revealed a striking sexual dimorphism in molecular signatures of the dorsal root ganglia (DRG) and spinal cord response, not observed at the nerve injection site. Mechanistically, intra-sciatic MBP(84-104) induced phospholipase C (PLC)-driven (females) and phosphoinositide 3-kinase-driven (males) phospholipid metabolism (tier 1). PLC/inositol trisphosphate receptor (IP3R) and estrogen receptor co-regulation in spinal cord yielded Ca2+-dependent nociceptive signaling induction in females that was suppressed in males (tier 2). IP3R inactivation by intrathecal xestospongin C attenuated the female-specific hypersensitivity induced by MBP(84-104). According to sustained sensitization in tiers 1 and 2, T cell–related signaling spreads to the DRG and spinal cord in females, but remains localized to the sciatic nerve in males (tier 3). These results are consistent with our previous finding that MBP(84-104)–induced pain is T cell–dependent. In summary, an autoantigenic peptide endogenously released in nerve injury triggers multisite, sex-specific transcriptome changes, leading to neuropathic pain only in female mice. MBP(84-104) acts through sustained co-activation of metabolic, estrogen receptor–mediated nociceptive, and autoimmune signaling programs.
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