Tuesday, April 29, 2025
4/29/2025
Therapeutics targeting TDP-43 to treat Alzheimer's disease and related disorders - TDP-43 is a mixed proteinopapthy in Alzheimer’s disease (AD), AD-TDP, based on substantial epidemiological data correlating TDP-43 inclusions with cognitive decline in AD patients. TDP-43 associated AD has been termed as limbic-predominant age-related TDP-43 encephalopathy (LATE) as well as other acronyms, underlying the newly-recognized importance of TDP-43 in AD (AD-TDP). AD is the most common cause of mid- to late-life cognitive impairment and dementia, afflicting ~30 million people worldwide Based on an extensive review of clinical and pathological studies, TDP-43 proteinopathy is associated with an amnestic dementia syndrome that occurs in older adults. A statistical analysis of attributable risk suggests that TDP-43 associated AD is a major public health issue accounting for up to 20% of cases of clinically diagnosed AD dementia. This TDP-43 proteinopathy is a distinct clinical and pathological entity from other TDP-43 associated diseases that may also be treatable with a TDP-43 targeted therapy, such as amyotrophic lateral sclerosis (ALS) and certain forms of frontotemporal lobar degeneration (FTLD-TDP). Therefore, successful completion of this project has the potential to identify TDP-43-based therapeutics for the treatment of other diseases where TDP-43 plays a major and causative role. We have discovered small molecules that bind to TDP-43 in such a way as to inhibit binding of RNA to TDP-43 and prevent TDP-43 aggregation, with activity suggestive of a therapeutic effect in three models: (1) human wild-type and mutant TDP-43 expressed in Drosophila, (2) induced motor neurons (iMNs) from C9orf72 patient-derived iPSCs, and (3) mice expressing human TDP-43 (Thy1 promotor). Evidence from 2-D NMR studies and computational docking analysis suggests that these inhibitors are binding to ribonucleotide recognition motif RRM2 which contains one of the amino acids involved in a critical and functionally-relevant salt bridge with RRM1. A recent PET imaging study describes a metabolic marker to potentially select AD-TDP patients for clinical trials based on ratios of FDG imaging in different regions of the brain. In this project we seek to discover, validate and develop new small- molecule inhibitors of nucleic acid binding to TDP-43 and TDP-43 aggregation inhibitors to treat AD-TDP. Aim 1 is the optimization of in vitro potency and drug-like properties of novel TDP-43 ligands including penetration into the brain and acceptable half-life and safety measures using a comprehensive battery of pharmaceutical industry-standard assays and criteria. Aim 2 involves target engagement studies using hTDP-43 transfected in HEK293T cells, patient-derived induced motor neurons from iPSCs, dynamic light scattering analysis of aggregation, and X-ray crystallography of ligands bound into TDP-43. Aim 3 is evaluation in animal models of TDP-43 pathology, initially using a Thy1 promoter followed by a hTDP-43 based mouse model that demonstrates cognitive impairment in the absence of locomotor deficits. Aim 4 includes IND-enabling studies, scale-up synthesis, multi-species PK and rodent toxicity.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).