Pharmacological inhibitors of cyclin-dependent kinases

The invention provides compositions and methods for treatment of amyloidogenic diseases. Such methods entail administering an agent that induces a beneficial immune response against an amyloid deposit in the patient. The methods are particularly useful for prophylactic and therapeutic treatment of Alzheimer's disease. In such methods, a suitable agent is Aβ peptide or an antibody thereto.

Prevention and treatment of amyloidogenic disease

The ribosomal S6 protein kinase p70 S6 kinase is known for its role in modulating cell-cycle progression, cell size, and cell survival. In response to mitogen stimulation, p70 S6 kinase activation up-regulates ribosomal biosynthesis and enhances the translational capacity of the cell. In Alzheimer's disease (AD), there is a marked increase in total tau protein in the form of abnormally hyperphosphorylated tau (PHF-tau) in neurons with neurofibrillary tangles (NFTs). In the present study, we investigated whether p70 S6 kinase activation is associated with PHF-tau accumulation in AD. By immunohistochemistry, we found that the levels of phosphorylated p70 S6 kinase (at Thr389 or at Thr421/Ser424) were increased in accordance with the progressive sequence of neurofibrillary changes according to Braak's criteria. Confocal microscopy showed that in AD brain, phosphorylated p70 S6 kinase appeared especially in neurons that are known to later develop NFTs. This pattern of neurons showed dot-like structures of phosphorylated p70 S6 kinase and hyperphosphorylated tau, which partially correlated with rab5 (endosome marker), lamp-1 (lysosome marker), and ubiquitin (ubiquitin-proteasomal system marker). By indirect enzyme-linked immunosorbent assay, phosphorylated p70 S6 kinase (Thr389 or Thr421/Ser424), total tau, and PHF-tau were found to be significantly increased in AD brain as compared to control cases. The levels of total p70 S6 kinase and p70 S6 kinase phosphorylated at Thr421/Ser424 showed significant correlations with the levels of both total tau and PHF-tau. Regression analyses revealed a significant dependence of total tau or PHF-tau on p70 S6 kinase phosphorylated at Thr421/Ser424 rather than at Thr389. The levels of ribosomal protein S6 as well as the levels of markers for the proteolytic system were also significantly increased in AD as compared to control brain. Using a SH-SY5Y neuroblastoma cell model, we found that 100 μmol/L zinc sulfate could induce p70 S6 kinase phosphorylation and activation, in particular at Thr421/Ser424. This up-regulation of the activated kinase resulted in an increased expression and phosphorylation of tau. Pretreatment of cells with rapamycin (an inhibitor of FRAP/mTOR which is the immediate upstream kinase of the p70 S6 kinase) attenuated the effects induced by zinc. In primary cultured neurons of rat cortical cortex, zinc sulfate treatment could repeat p70 S6 kinase phosphorylation and activation at Thr421/Ser424, followed by increased expression and phosphorylation of tau. Taken together, these data suggest that activated p70 S6 kinase could mediate an up-regulation of tau translation. The partial co-localization of phosphorylated p70 S6 kinase with rab5, lamp-1 and ubiquitin, or PHF-tau with ubiquitin suggests that the activated proteolytic system might not be sufficient to degrade the over-produced and over-phosphorylated tau protein. A p70 S6 kinase modulated up-regulation of tau translation might contribute to PHF-tau accumulation in neurons with neurofibrillary changes.

Up-regulation of phosphorylated/activated p70 S6 kinase and its relationship to neurofibrillary pathology in Alzheimer's disease.

The invention provides improves agents and methods for treatment of diseases associated with amyloid deposits of Aβ in the brain of a patient. Preferred agents include humanized antibodies.

Humanized antibodies that recognize beta amyloid peptide

Nucleolin is a multifunctional protein localized primarily in the nucleolus, but also found in the nucleoplasm, cytoplasm and cell membrane. It is involved in several aspects of DNA metabolism, and participates extensively in RNA regulatory mechanisms, including transcription, ribosome assembly, mRNA stability and translation, and microRNA processing. Nucleolin's implication in disease is linked to its ability to associate with target RNAs via its four RNA-binding domains and its arginine/glycin-rich domain. By modulating the post-transcriptional fate of target mRNAs, which typically bear AU-rich and/or G-rich elements, nucleolin has been linked to cellular events that influence disease, notably cell proliferation and protection against apoptotic death. Through its diverse RNA functions, nucleolin is increasingly implicated in pathological processes, particularly cancer and viral infection. Here, we review the RNA-binding activities of nucleolin, its influence on gene expression patterns, and its impact upon diseases. We also discuss the rising interest in targeting nucleolin therapeutically.

https://www.tandfonline.com/doi/pdf/10.4161/rna.19718

RNA-binding protein nucleolin in disease

Cdc2 phosphorylation of nucleolin demarcates mitotic stages and Alzheimer’s disease pathology

This invention is directed to methods and compositions for preventing aggregation of amyloid β-protein (βAP) aggregation. Aggregation of amyloid β-protein is associated with the deposition of amyloid in the brain. Amyloid β-protein-binding compounds such as transthyretin are described which form complexes with βAP and prevent formation of amyloid. This invention also identifies the serine 6 mutation in the TTR gene as predictive of person at risk for developing βAP associated amyloidosis.

METHOD OF PREVENTING AGGREGATION OF AMYLOID β-PROTEIN

Methods for the detection of soluble amyloid β-protein (βAP) or soluble transthyretin (TTR)

L'invention porte sur des procedes et compositions prevenant l'agglutination des proteines β amyloides (βAP), laquelle est liee au depot d'amyloides dans le cerveau; et comporte la description de composes de fixation de la proteine β amyloide tels que la transthyretine qui forment avec elle des complexes empechant la formation d' amyloides. L'invention permet en outre d'identifier la mutation de la serine 6 dans le gene TTR, laquelle constitue un signe de predisposition au risque de developpement d'une amylose associee a la βAP.

Alexander L. Schwarzman

Papers

Cdc2 phosphorylation of nucleolin demarcates mitotic stages and Alzheimer’s disease pathology

METHOD OF PREVENTING AGGREGATION OF AMYLOID β-PROTEIN

Methods for the detection of soluble amyloid β-protein (βAP) or soluble transthyretin (TTR)

PROCEDE EMPECHANT L'AGGLUTINATION DES PROTEINES β AMYLOIDES