1. Proenkephalin A 119-159, a stable proenkephalin A precursor fragment identified in human circulation
A Ernst, J Köhrle, A Bergmann Peptides. 2006 Jul;27(7):1835-40. doi: 10.1016/j.peptides.2006.03.008. Epub 2006 Apr 18.
In this report, we describe a newly developed sandwich immunoassay using antibodies against the proenkephalin A 119-159 peptide (PENK A 119-159). PENK A 119-159 immunoreactivity was detectable in the circulation of human blood donors and in cerebrospinal fluid (CSF) of patients without a neurologic disorder. The concentration was about 100 times higher in CSF than in serum. Analytical reversed phase HPLC revealed that PENK A 119-159 is the main immunoreactivity in human circulation and CSF. Moreover, PENK A 119-159 is stable in vitro for at least 48 h at room temperature as compared to the low stability of the peptides methionine- and leucine-enkephalin. This suggests the use of PENK A 119-159 measurement as surrogate molecule for the release of the mature peptides derived from proenkephalin A.
2. Proenkephalin A Adds No Incremental Prognostic Value After Acute Ischemic Stroke
Philipp Gruber, Felix Fluri, Juliane Schweizer, Andreas Luft, Beat Müller, Mirjam Christ-Crain, Mira Katan Clin Appl Thromb Hemost. 2020 Jan-Dec;26:1076029619895318. doi: 10.1177/1076029619895318.
Objective: The aim of this study was to confirm previous observations that proenkephalin A (PENK-A) may serve as prognostic marker in the setting of acute ischemic stroke in a large stroke cohort. Methods: The plasma concentration of PENK-A was measured within 72 hours of symptom onset in 320 consecutively enrolled patients with stroke. The primary outcome measures were unfavorable functional outcome (modified Rankin Scale score 0-2 vs 3-6) and mortality within 90 days. Logistic and cox proportional regression analyses were fitted to estimate odds ratios (ORs), hazard ratios (HRs) and 95% confidence intervals (CIs), respectively, for the association between PENK-A and the primary outcome measures. Results: After adjusting for demographic and vascular risk factors, PENK-A was neither independently associated with functional outcome (OR: 1.29, 95% CI: 0.16-10.35) nor mortality (HR: 1.02, 95% CI: 0.14-7.33). Conclusion: Among patients with acute stroke, PENK-A does not serve as an independent prognostic marker in this external validation cohort.
3. A neuropeptide precursor in cerebellum: proenkephalin exists in subpopulations of both neurons and astrocytes
B A Spruce, R Curtis, G P Wilkin, D M Glover EMBO J. 1990 Jun;9(6):1787-95. doi: 10.1002/j.1460-2075.1990.tb08303.x.
The adult rat cerebellum has minimal enkephalin immunoreactivity and is devoid of opiate-binding activity. Using novel monoclonal antibodies to the mammalian enkephalin precursor, we describe the immunofluorescent detection of proenkephalin, in the absence of mature enkephalin peptides, in subpopulations of rat cerebellar neurons and astrocytes. In cryostat sections, neurons that express proenkephalin include Golgi cells, macroneurons within deep cerebellar nuclei and a subpopulation of Purkinje cells. Proenkephalin messenger RNA and protein are present in subpopulations of both grey and white matter astrocytes, but not Bergmann glia. In dissociated glial culture, proenkephalin is expressed in process-bearing astrocytes, apparently in association with a subset of intermediate filaments. Proenkephalin within astrocytes is not seen until the second postnatal week and increases through to adulthood. Neuropeptide gene expression adds to the growing range of neuronal-type properties glial cells can display.
