A novel DYRK1A (Dual specificity tyrosine phosphorylation‐regulated kinase 1A) inhibitor for the treatment of Alzheimer's disease: effect on Tau and amyloid pathologies in vitro

Abstract

The dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) gene is located within the Down Syndrome (DS) critical region on chromosome 21 and is implicated in the generation of Tau and amyloid pathologies that are associated with the early onset Alzheimer's Disease (AD) observed in DS. DYRK1A is also found associated with neurofibrillary tangles in sporadic AD and phosphorylates key AD players (Tau, amyloid precursor, protein, etc). Thus, DYRK1A may be an important therapeutic target to modify the course of Tau and amyloid beta (Ab) pathologies. Here, we describe EHT 5372 (methyl 9-(2,4-dichlorophenylamino) thiazolo[5,4-f]quinazoline-2-carbimidate), a novel, highly potent (IC 50 = 0.22 nM) DYRK1A inhibitor with a high degree of selectivity over 339 kinases. Models in which inhibition of DYRK1A by siRNA reduced and DYRK1A over-expression induced Tau phosphorylation or Ab production were used. EHT 5372 inhibits DYRK1A-induced Tau phosphorylation at multiple AD-relevant sites in biochemical and cellular assays. EHT 5372 also normalizes both Ab-induced Tau phosphorylation and DYRK1A-stimulated Ab production. DYRK1A is thus as a key element of Abmediated Tau hyperphosphorylation, which links Tau and amyloid pathologies. EHT 5372 and other compounds in its class warrant in vivo investigation as a novel, high-potential therapy for AD and other Tau opathies.

Directed evolution of a picomolar-affinity, high-specificity antibody targeting phosphorylated tau

“…7a, second row). These results indicate that the binding of wild-type pT231 scFv and mutant 3.24 requires phosphorylation of tau, and as reported previously, the tau expressed in HEK293 cells is phosphorylated (49,50). In order to further assess the specificity of the scFvs, we generated point mutants of human tau at the target phosphorylation site (T231) either incapable of phosphorylation (T231A) or pseudophosphorylated (T231E).…”

“…2-4 µg of the PCR product was digested with 0.0015 unit of DNase I (New England BioLabs) per µL in 100 µL of reaction mixture for 15 min at room temperature. Fragments of 10-50 bp were purified from 2 % low melting agarose gel by electrophoresis and then resuspended in 50 Fluorescence activated cell sorting was used to screen for yeast cells displaying high-affinity scFvs. 10x library diversity of cells were pelleted and washed with 1 mL of phosphate-buffered saline with bovine serum albumin (PBSA, 8 g/L NaCl, 0.2 g/L KCl, 1.44 g/L Na 2 HPO 4 , 0.24 g/L KH 2 PO 4 , 1 g/L bovine serum albumin, pH 7.4) twice.…”

Normalizing the gene dosage of Dyrk1A in a mouse model of Down syndrome rescues several Alzheimer's disease phenotypes

“…In this regard, several new molecules that inhibit DYRK1A activity have been proven to reduce some AD phenotypes such as tau expression or phosphorylation, APP levels or Aβ load (Kim et al, 2016;Abbassy et al, 2015;Contadeur et al, 2015). Future studies should test the efficacy of the only DYRK1A inhibitor that has been so far tested in humans, epigallocatechin-gallate (EGCG) (De la Torre et al, 2014; to prevent different AD-associated alterations.…”

Roles of tau protein in health and disease

“…CK1δ may also be an important candidate tau kinase since it phosphorylates tau on 46 sites [189] and colocalises with tau pathology in AD brain [440]. DYRK1A phosphorylates tau on three sites and inhibiting DYRK1A has recently been proposed as a therapeutic approach for AD [91]. Notably, the ability of DYRK1A to phosphorylate Thr212 on tau, implicates DYRK1A as a potential priming kinase, facilitating subsequent GSK3β phosphorylation of tau on the nearby residue Ser208 [426].…”