The Potential of Serratiopetidase and Lumbrokinase for the Degradation of Prion Peptide 106-126 - an In Vitro and In Silico Perspective

Abnormal Expression of Proteolytic Stress-Related Proteins and Protective Effect of Fibrinolytic Enzymes in Prion Diseases

Prion diseases are fatal, irreversible, and infectious neurodegenerative diseases caused by proteinase K-resistant prion protein (PrPSc). Against PrPSc, several endogenous proteases involved in cellular degradation mechanisms can be activated to remove PrPSc. However, since PrPSc shows proteinase K resistance, we presumed that undegradable PrPSc induces positive feedback on the overactivation of the cellular degradation mechanisms and is correlated with proteolytic stress and exacerbation of the progression of prion diseases. We investigated the expression pattern of proteolytic stress-related proteins in the brains of ME7 scrapie-infected mice at 7 months postinfection and sporadic Creutzfeldt-Jakob disease (CJD) patients using western blotting and immunohistochemistry (IHC). In addition, we analyzed the 3D structure and binding complexes of prion protein (PrP) with nattokinase and lumbrokinase using in silico programs, including SWISS-MODEL and HawkDock. To fundamentally reduce proteolytic stress by the degradation of PrPSc, we performed an in vitro evaluation of the PrPSc degradation abilities of fibrinolytic enzymes, including nattokinase and lumbrokinase. Furthermore, we assessed the protective effects of nattokinase and lumbrokinase in ME7 scrapie-infected mice. We observed an abnormal accumulation of proteolytic stress-related proteins, including CD10, cathepsin B, cathepsin D, and matrix metalloproteinase 9 (MMP9), in the brains of ME7 scrapie-infected mice and sporadic CJD patients. In addition, we identified that nattokinase and lumbrokinase can stably bind to PrP. Furthermore, we identified significant in vitro degradation of PrPSc derived from ME7 scrapie-infected mice and sporadic CJD patients by nattokinase and lumbrokinase. Last, we found in vivo protective effects of nattokinase and lumbrokinase against prion disease in ME7 scrapie-infected mice. To the best of our knowledge, this is the first report on the identification of proteolytic stress-related novel potential biomarkers and the therapeutic potential of nattokinase and lumbrokinase for prion diseases.

Degradation of pathogenic amyloids induced by matrix metalloproteinase-9

Over the past decade, the greatest promise for treating severe and currently incurable systemic and neurodegenerative diseases has turned to agents capable of effectively degrading pathological amyloid deposits without causing side effects. Specifically, amyloid destruction observed in immunotherapy is hypothesized to occur through activation of proteolytic enzymes. This study examines poorly understood effects of an immune enzyme, extracellular matrix metalloproteinase-9 (MMP9), on amyloids associated with Alzheimer's and Parkinson's diseases, lysozyme, insulin, and dialysis-related amyloidoses. The study establishes the universality of MMP9's effect on various amyloids, with its efficacy largely depending on the fibrillar cluster size. Irreversible amyloid degradation by MMP9 is attributed to the destruction of intramolecular interactions rather than intermolecular hydrogen bonds in the fibril backbone. This process results in the loss of ordered fiber structure without reducing aggregate size or increasing cytotoxicity. Thus, MMP9 can mitigate side effects of anti-amyloid therapy associated with the formation of low-molecular-weight degradation products that may accelerate fibrillogenesis and amyloid propagation between tissues and organs. MMP9 shows promise as a component of safe anti-amyloid drugs by enhancing the accessibility of binding sites through "loosening" amyloid clusters, which facilitates subsequent fragmentation and monomerization by other enzymes.

Exploring the amyloid degradation potential of nanoformulated carrageenan-bridging in vitro and in vivo perspectives

Amyloids, with their β-sheet-rich structure, contribute to diabetes, neurodegenerative diseases, and amyloidosis by aggregating within diverse anatomical compartments. Insulin amyloid (IA), sharing structural resemblances with amyloids linked to neurological disorders, acts as a prototype, while compounds capable of degrading these fibrils hold promise as therapeutic agents for amyloidosis intervention. In this research, liposomal nanoformulated iota carrageenan (nCG) was formulated to disrupt insulin amyloids, demonstrating about a 17-20 % higher degradation efficacy compared to conventional carrageenan through thioflavin T fluorescence, dynamic light scattering analysis, and turbidity quantification. The biocompatibility of the nCG and nCG-treated insulin amyloids was evaluated through MTT assay, live-dead cell assay on V79 cells, and hemolysis testing on human blood samples to establish their safety for use in vitro. Zebrafish embryos were utilized to assess in vivo biocompatibility, while adult zebrafish were employed to monitor the degradation capacity of IA post subcutaneous injection, with fluorescence emitted by the fish captured via IVIS. This demonstrated that the formulated nCG exhibited superior anti-amyloid efficacy compared to carrageenan alone, while both materials demonstrated biocompatibility. Furthermore, through docking simulations, an exploration was conducted into the molecular mechanisms governing the inhibition of the target protein pancreatic insulin by carrageenan.

The potential of lumbrokinase and serratiopeptidase for the degradation of Aβ 1-42 peptide - an in vitro and in silico approach

BACKGROUND

Alzheimer's disease (AD) is diagnosed with the deposition of insoluble β-amyloid (Aβ) peptides in the neuropil of the brain leading to dementia. The extracellular deposition of the fibrillar Aβ peptide on the neurons is known as senile plaques. Therefore, Aβ degradation and clearance from the human body is a promising therapeutic approach in the medication of AD.

METHODS

In the current study, the enzyme lumbrokinase (LK) was extracted and purified from earthworm and its activity was utilized toward Aβ 1-42 amyloids degradation in vitro alongside with an additional enzyme serratiopeptidase (SP) considering nattokinase (NK) as a standard.

RESULTS

The output of this study revealed that preformed Aβ 1-42 amyloids was disintegrated by both LK and SP, as demonstrated from fluorescence assay using Thioflavin T dye. In addition, dynamic light scattering study revealed the lower size of the preformed fibrils Aβ 1-42 at various time intervals after incubation with the enzymes LK and SP. Furthermore, in silico approach showed high affinity thermodynamically favorable interaction of LK as well as SP toward Aβ 1-42 amyloid. Finally, the toxicity of degraded preformed Aβ 1-42 amyloid was assessed by MTT assay which showed reduced toxicity of enzyme treated Aβ 1-42 amyloid compared to only Aβ 1-42 amyloid.

CONCLUSION

The findings of the present study indicated that LK and SP, not only had Aβ 1-42 amyloid degrading potential, but also could reduce the toxicity which can make them a suitable drug candidate for AD. Furthermore, the in vivo studies are needed to be executed in future.

Roles of Apigenin and Nepetin in the Assembly Behavior and Cytotoxicity of Prion Neuropeptide PrP106-126

Development of potential inhibitors to prevent prion protein (PrP) fibrillation is a therapeutic strategy for prion diseases. The prion neuropeptide PrP106-126, a research model of abnormal PrP (PrPSc), presents similar physicochemical and biochemical characters to PrPSc, which is also a target of potential inhibitors against prion deposition. Many flavones have antioxidant, anti-inflammatory, and antibacterial properties, and they are applied in treating prion disorder and other amyloidosis as well. However, the inhibition mechanism of flavones on PrP106-126 fibrillation is still unclear. In the current work, apigenin and nepetin were used to suppress the aggregation of PrP106-126 and to alleviate the peptide-induced cytotoxicity. The results showed that apigenin and nepetin impeded the fibril formation of PrP106-126 and depolymerized the preformed fibrils. They were bound to PrP106-126 predominantly by hydrophobic and hydrogen bonding interactions. In addition, both flavones upregulated cell viability and decreased membrane leakage through reducing peptide oligomerization. The differences in inhibition and cell protection between the two small molecules were presumably attributed to the substitution of hydroxyl and methoxy groups in nepetin, which demonstrated the significant structure-function relationship of flavones with prion neuropeptide and the prospect of flavonoids as drug candidates against prion diseases.

Are fibrinaloid microclots a cause of autoimmunity in Long Covid and other post-infection diseases?

It is now well established that the blood-clotting protein fibrinogen can polymerise into an anomalous form of fibrin that is amyloid in character; the resultant clots and microclots entrap many other molecules, stain with fluorogenic amyloid stains, are rather resistant to fibrinolysis, can block up microcapillaries, are implicated in a variety of diseases including Long COVID, and have been referred to as fibrinaloids. A necessary corollary of this anomalous polymerisation is the generation of novel epitopes in proteins that would normally be seen as 'self', and otherwise immunologically silent. The precise conformation of the resulting fibrinaloid clots (that, as with prions and classical amyloid proteins, can adopt multiple, stable conformations) must depend on the existing small molecules and metal ions that the fibrinogen may (and is some cases is known to) have bound before polymerisation. Any such novel epitopes, however, are likely to lead to the generation of autoantibodies. A convergent phenomenology, including distinct conformations and seeding of the anomalous form for initiation and propagation, is emerging to link knowledge in prions, prionoids, amyloids and now fibrinaloids. We here summarise the evidence for the above reasoning, which has substantial implications for our understanding of the genesis of autoimmunity (and the possible prevention thereof) based on the primary process of fibrinaloid formation.

Phosphorus-carrying cascade molecules: inner architecture to biomedical applications

Cascade molecules are nearly uniform-sized macromolecules of small molecules or linear polymer cores built around symmetric branching units. A wide range of biological properties can be achieved with phosphorus-containing dendrimers, depending on their terminal functions, ranging from biomaterials to imaging, drug delivery, and acting as a drug by themselves. This feature article presents significant examples of phosphorus-containing dendrimers used to develop biochips, support cell cultures, carry or deliver biomacromolecules and drugs, bioimaging, and combinational benefits. Because of the thermal stability, ferrocene function, and physical and chemical properties of phosphorus, dendrimers show greater rigidity, mobility, and strength. These dendrimers will be discussed as having a favorable effect on cell growths, especially on neuronal cells, as well as human immune cells like natural killer cells and monocytes, which have a crucial part in preventing cancerous and viral infections. Several phosphorus dendrimers are effective as drugs by themselves (drug per se) and show their activity against neurodegenerative diseases, cancer, inflammation, ocular hypertension, and transmissible spongiform encephalopathies (TSEs) in both in vivo and in vitro. The present review discusses the synthetic route, fabrications, and biomedical applications of phosphorus-containing dendrimers. The toxicity of these dendrimers was also reported.