scholarly journals Intraoperative visualization of nerves using a myelin protein-zero specific fluorescent tracer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tessa Buckle ◽  
Albertus. W. Hensbergen ◽  
Danny M. van Willigen ◽  
Frank Bosse ◽  
Kevin Bauwens ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Cyanine Dye ◽  
Myelin Protein ◽  
Nerve Sparing ◽  
Myelin Protein Zero ◽  
Fluorescent Tracer ◽  
Biodistribution Data ◽  
Protein Zero

Abstract Background Surgically induced nerve damage is a common but debilitating side effect in oncological surgery. With the aim to use fluorescence guidance to enable nerve-sparing interventions in future surgery, a fluorescent tracer was developed that specifically targets myelin protein zero (P0). Results Truncated homotypic P0 protein-based peptide sequences were C-terminally functionalized with the far-red cyanine dye Cy5. The lead compound Cy5-P0101–125 was selected after initial solubility, (photo)physical and in vitro evaluation (including P0-blocking experiments). Cy5-P0101–125 (KD = 105 ± 17 nM) allowed in vitro and ex vivo P0-related staining. Furthermore, Cy5-P0101–125  enabled in vivo fluorescence imaging of the Sciatic nerve in mice after local intravenous (i.v.) administration and showed compatibility with a clinical fluorescence laparoscope during evaluation in a porcine model undergoing robot-assisted surgery. Biodistribution data revealed that i.v. administered [111In]In-DTPA-P0101–125 does not enter the central nervous system (CNS). Conclusion P0101–125 has proven to be a potent nerve-specific agent that is able to target P0/myelin under in vitro, ex vivo, and in vivo conditions without posing a threat for CNS-related toxicity.

scholarly journals A Rare Myelin Protein Zero (MPZ) Variant Alters Enhancer Activity In Vitro and In Vivo

PLoS ONE ◽  
2010 ◽  
Vol 5 (12) ◽  
pp. e14346 ◽  
Author(s):  
Anthony Antonellis ◽  
Megan Y. Dennis ◽  
Grzegorz Burzynski ◽  
Jimmy Huynh ◽  
Valerie Maduro ◽  
...  
Keyword(s):  
Myelin Protein ◽  
Myelin Protein Zero ◽  
Enhancer Activity ◽  
Protein Zero

In silico and in vitro effects of the I30T mutation on myelin protein zero instability in the cell membrane

2019 ◽  
Vol 44 (2) ◽  
pp. 671-683
Author(s):  
Fatemeh Ghanavatinejad ◽  
Zahra Pourteymourfard‐Tabrizi ◽  
Karim Mahnam ◽  
Abbas Doosti ◽  
Ameneh Mehri‐Ghahfarrokhi ◽  
...  
Keyword(s):  
Cell Membrane ◽  
In Silico ◽  
Myelin Protein ◽  
Myelin Protein Zero ◽  
In Vitro Effects ◽  
Protein Zero

scholarly journals A novel myelin protein zero transgenic zebrafish designed for rapid readout of in vivo myelination

Glia ◽  
2019 ◽  
Vol 67 (4) ◽  
pp. 650-667 ◽  
Author(s):  
Marnie A. Preston ◽  
Lisbet T. Finseth ◽  
Jennifer N. Bourne ◽  
Wendy B. Macklin
Keyword(s):  
Myelin Protein ◽  
Transgenic Zebrafish ◽  
Myelin Protein Zero ◽  
Protein Zero

Myelination during fracture healing in vivo in myelin protein zero (p0) transgenic medaka line

Bone ◽  
2020 ◽  
Vol 133 ◽  
pp. 115225 ◽  
Author(s):  
Yusuke Dodo ◽  
Masahiro Chatani ◽  
Yuki Azetsu ◽  
Masahiro Hosonuma ◽  
Akiko Karakawa ◽  
...  
Keyword(s):  
Fracture Healing ◽  
Myelin Protein ◽  
Myelin Protein Zero ◽  
Protein Zero

scholarly journals A nonsense mutation in myelin protein zero causes congenital hypomyelination neuropathy through altered P0 membrane targeting and gain of abnormal function

2018 ◽  
Vol 28 (1) ◽  
pp. 124-132 ◽  
Author(s):  
Pietro Fratta ◽  
Francesca Ornaghi ◽  
Gabriele Dati ◽  
Desirée Zambroni ◽  
Paola Saveri ◽  
...  
Keyword(s):  
Nonsense Mutation ◽  
Plasma Membranes ◽  
Severe Form ◽  
Myelin Protein ◽  
Hereditary Neuropathy ◽  
Myelin Protein Zero ◽  
Structural Protein ◽  
Nonsense Mediated Decay ◽  
Protein Zero

Abstract Protein zero (P0) is the major structural protein in peripheral myelin, and mutations in the Myelin Protein Zero (Mpz) gene produce wide-ranging hereditary neuropathy phenotypes. To gain insight in the mechanisms underlying a particularly severe form, congenital hypomyelination (CH), we targeted mouse Mpz to encode P0Q215X, a nonsense mutation associated with the disease, that we show escapes nonsense mediated decay and is expressed in CH patient nerves. The knock-in mice express low levels of the resulting truncated protein, producing a milder phenotype when compared to patients, allowing to dissect the subtle pathogenic mechanisms occurring in otherwise very compromised peripheral myelin. We find that P0Q215X does not elicit an unfolded protein response, which is a key mechanism for other pathogenic MPZ mutations, but is instead in part aberrantly trafficked to non-myelin plasma membranes and induces defects in radial sorting of axons by Schwann cells. We show that the loss of the C-terminal Tyr-Ala-Met-Leu motif is responsible for P0 mislocalization, as its addition is able to restore correct P0Q215X trafficking in vitro. Lastly, we show that P0Q215X acts through dose-dependent gain of abnormal function, as wild-type P0 is unable to rescue the hypomyelination phenotype. Collectively, these data indicate that alterations at the premyelinating stage, linked to altered targeting of P0, may be responsible for CH, and that different types of gain of abnormal function produce the diverse neuropathy phenotypes associated with MPZ, supporting future allele-specific therapeutic silencing strategies.

scholarly journals A nonsense mutation in Myelin Protein Zero causes congenital hypomyelination neuropathy through altered P0 membrane targeting and gain of abnormal function

2018 ◽  
Author(s):  
Pietro Fratta ◽  
Francesca Ornaghi ◽  
Gabriele Dati ◽  
Desirée Zambroni ◽  
Paola Saveri ◽  
...  
Keyword(s):  
Nonsense Mutation ◽  
Plasma Membranes ◽  
Severe Form ◽  
Myelin Protein ◽  
Hereditary Neuropathy ◽  
Myelin Protein Zero ◽  
Structural Protein ◽  
Nonsense Mediated Decay ◽  
Protein Zero

AbstractProtein Zero (P0) is the major structural protein in peripheral myelin and mutations in the Myelin Protein Zero (Mpz) gene produce wide ranging hereditary neuropathy phenotypes. To gain insight in the mechanisms underlying a particularly severe form, congenital hypomyelination (CH), we targeted mouse Mpz to encode P0Q215X, a nonsense mutation associated with the disease, that we show escapes nonsense mediated decay and is expressed in CH patient nerves. The knock-in mice express low levels of the resulting truncated protein, producing a milder phenotype when compared to patients, allowing to dissect the subtle pathogenic mechanisms occurring in otherwise very compromised peripheral myelin. We find that P0Q215X does not elicit an unfolded protein response, which is a key mechanism for other pathogenic MPZ mutations, but is instead aberrantly trafficked to non-myelin plasma membranes and induces defects in radial sorting of axons by Schwann cells (SC). We show that the loss of the C-terminal YAML motif is responsible for P0 mislocalisation, as its addition is able to restore correct P0Q215X trafficking in vitro. Lastly, we show that P0Q215X acts through dose-dependent gain of abnormal function, as wildtype P0 is unable to rescue the hypomyelination phenotype. Collectively, these data indicate that alterations at the premyelinating stage, linked to altered targeting of P0, may be responsible for CH, and that different types of gain of abnormal function produce the diverse neuropathy phenotypes associated with MPZ, supporting future allele-specific therapeutic silencing strategies.

scholarly journals Neuropathy-Associated Egr2 Mutants Disrupt Cooperative Activation of Myelin Protein Zero by Egr2 and Sox10

2007 ◽  
Vol 27 (9) ◽  
pp. 3521-3529 ◽  
Author(s):  
Scott E. LeBlanc ◽  
Rebecca M. Ward ◽  
John Svaren
Keyword(s):  
Binding Sites ◽  
Myelin Protein ◽  
Myelin Protein Zero ◽  
Early Growth Response ◽  
Expression Of Genes ◽  
Myelin Associated Glycoprotein ◽  
Responsive Element ◽  
Protein Zero ◽  
Cooperative Activation

ABSTRACT Dominant mutations in the early growth response 2 (Egr2/Krox20) transactivator, a critical regulator of peripheral myelin development, have been associated with peripheral myelinopathies. These dominant mutants interfere with the expression of genes required for myelination by Schwann cells, including that for the most abundant peripheral myelin protein, Myelin protein zero (Mpz). In this study, we show that Egr2 mutants specifically affect an Egr2-responsive element within the Mpz first intron that also contains binding sites for the transcription factor Sox10. Furthermore, Egr2 activation through this element is impaired by mutation of the Sox10 binding sites. Using chromatin immunoprecipitation assays, we found that Egr2 and Sox10 bind to this element in myelinating sciatic nerve and that a dominant Egr2 mutant does not perturb Egr2 binding but rather attenuates binding of Sox10 to the Mpz intron element. Sox10 binding at other sites of Egr2/Sox10 synergy, including a novel site in the Myelin-associated glycoprotein (Mag) gene, is also reduced by the dominant Egr2 mutant. These results provide the first demonstration of binding of Egr2/Sox10 to adjacent sites in vivo and also demonstrate that neuropathy-associated Egr2 mutants antagonize binding of Sox10 at specific sites, thereby disrupting genetic control of the myelination program.

scholarly journals Neuron-specific biomarkers predict hypo- and hyperalgesia in individuals with diabetic peripheral neuropathy

Diabetologia ◽  
2021 ◽  
Author(s):  
Jakob Morgenstern ◽  
Jan B. Groener ◽  
Johann M. E. Jende ◽  
Felix T. Kurz ◽  
Alexander Strom ◽  
...  
Keyword(s):  
Peripheral Neuropathy ◽  
Diabetic Neuropathy ◽  
Light Chain ◽  
Diabetic Peripheral Neuropathy ◽  
Myelin Protein ◽  
Myelin Protein Zero ◽  
Neurofilament Light Chain ◽  
Neurofilament Light ◽  
Protein Zero

Abstract Aims/hypothesis The individual risk of progression of diabetic peripheral neuropathy is difficult to predict for each individual. Mutations in proteins that are responsible for the process of myelination are known to cause neurodegeneration and display alteration in experimental models of diabetic neuropathy. In a prospective observational human pilot study, we investigated myelin-specific circulating mRNA targets, which have been identified in vitro, for their capacity in the diagnosis and prediction of diabetic neuropathy. The most promising candidate was tested against the recently established biomarker of neural damage, neurofilament light chain protein. Methods Schwann cells were cultured under high-glucose conditions and mRNAs of various myelin-specific genes were screened intra- and extracellularly. Ninety-two participants with type 2 diabetes and 30 control participants were enrolled and evaluated for peripheral neuropathy using neuropathy deficit scores, neuropathy symptom scores and nerve conduction studies as well as quantitative sensory testing at baseline and after 12/24 months of a follow-up period. Magnetic resonance neurography of the sciatic nerve was performed in 37 individuals. Neurofilament light chain protein and four myelin-specific mRNA transcripts derived from in vitro screenings were measured in the serum of all participants. The results were tested for associations with specific neuropathic deficits, fractional anisotropy and the progression of neuropathic deficits at baseline and after 12 and 24 months. Results In neuronal Schwann cells and human nerve sections, myelin protein zero was identified as the strongest candidate for a biomarker study. Circulating mRNA of myelin protein zero was decreased significantly in participants with diabetic neuropathy (p < 0.001), whereas neurofilament light chain protein showed increased levels in participants with diabetic neuropathy (p < 0.05). Both variables were linked to altered electrophysiology, fractional anisotropy and quantitative sensory testing. In a receiver-operating characteristic curve analysis myelin protein zero improved the diagnostic performance significantly in combination with a standard model (diabetes duration, age, BMI, HbA1c) from an AUC of 0.681 to 0.836 for the detection of diabetic peripheral neuropathy. A follow-up study revealed that increased neurofilament light chain was associated with the development of a hyperalgesic phenotype (p < 0.05), whereas decreased myelin protein zero predicted hypoalgesia (p < 0.001) and progressive loss of nerve function 24 months in advance (HR of 6.519). Conclusions/interpretation This study introduces a dynamic and non-invasive assessment strategy for the underlying pathogenesis of diabetic peripheral neuropathy. The diagnosis of axonal degeneration, associated with hyperalgesia, and demyelination, linked to hypoalgesia, could benefit from the usage of neurofilament light chain protein and circulating mRNA of myelin protein zero as potential biomarkers. Graphical abstract

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

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