Biology subjects

Renganathan, S.

Publications and source records attributed to Renganathan, S..

4 recordsLinked to original sources

bioRxiv2026

Restoring multiple TDP-43 cryptic targets, but not solely Unc13a, rescues motor neuron disease

Dysfunction of TAR DNA-binding protein 43kDa (TDP-43) underlies amyotrophic lateral sclerosis (ALS), a neurodegenerative disorder with limited therapeutic options. While current therapeutic approaches are designed to individually target unique cryptic exons of TDP-43 such as UNC13A, the sufficiency of such a strategy to mitigate motor neuron disease remains unclear. Using a mouse model lacking TDP-43 in spinal motor neurons which mimics early stages of ALS, we show that the exclusion of Unc13a cryptic exon fails to mitigate motor neuron disease. In contrast, the restoration of multiple TDP-43 cryptic targets, including Unc13a, attenuated motor neuron loss, and rescued motor neuron disease. Additionally, compared to brain neurons, spinal motor neurons accumulate markedly lower amounts of Unc13a cryptic exons in mice and humans, suggesting that the contribution of this TDP-43 cryptic target to spinal motor neuron loss may be limited. Together, these results strongly support ALS therapeutic strategies designed to simultaneously restore multiple TDP-43 cryptic targets to attenuate spinal motor neuron loss.

neuroscience↗

bioRxiv2026

Prevention of Unc13a cryptic splicing is sufficient to preserve memory

TDP-43 dysfunction is thought to underlie frontotemporal dementia and limbic-predominant age-related TDP-43 encephalopathy, neurodegenerative dementias currently without effective therapy. Therapeutic strategies are designed to correct individual cryptic targets of TDP-43, such as UNC13A, whereby its cryptic splicing compromises synaptic function, yet the sufficiency of such an approach to prevent memory deficits is unclear. Using a forebrain neuron-specific TDP-43 knockout mouse model that recapitulates TDP-43 dysfunction occurring during early stages of human disorders, we found here that prevention of cryptic splicing to include that of Unc13a attenuated memory deficits. We show that genetic ablation of Unc13a cryptic exon solely in such TDP-43 knockout mice is sufficient to preserve cognition, supporting the clinical value of targeting UNC13A to mitigate memory deficits. Prevention of cryptic splicing of multiple targets of TDP-43 additionally attenuate neuron loss. For optimal outcomes in TDP-43 related dementias, these findings thus strongly support strategies designed to repress cryptic splicing of multiple targets of TDP-43, including UNC13A.

pathology↗

bioRxiv2026

Tauopathy primes co-filament assembly and dysfunction of TDP-43

While most Alzheimers disease (AD) which is associated with Limbic Predominant Age-related TDP-43 Encephalopathy (LATE) exhibits accelerated brain atrophy, the pathogenic mechanism remains elusive. We show here, in mice harboring depositions of amyloid-{beta} and tau, the age-dependent emergence of TDP-43 proteinopathy. We demonstrate that TDP-43 dysfunction facilitates caspase 3-mediated endoproteolysis of tau, accelerates tauopathy and exacerbates neuron loss. Unexpectedly, we found that the emergence and spread of TDP-43 proteinopathy is associated with the spread of tauopathy and correlated with co-filament assembly of tau and TDP-43. Importantly, TDP-43 dysfunction precedes such co-filament assembly and TDP-43 cytoplasmic aggregates. Consistent with the idea that tauopathy could prime co-filament assembly and proteinopathy of TDP-43 to exacerbate neurodegeneration, we found tau co-filament assembly with TDP-43 in AD and AD-LATE cases. These findings suggest that TDP-43 dysfunction accelerates tauopathy, which, in turn, primes co-filament assembly and dysfunction of TDP-43 to exacerbate neuron loss in AD-LATE, a pathogenic mechanism disclosing novel targets and therapeutic strategies.

neuroscience↗

bioRxiv2025

Symptomatic treatment by a BBB-permeable AAV engineered to restore TDP-43 function slows motor neuron disease and prevents paralysis

TAR DNA-binding protein 43kDa (TDP-43) dysfunction is an early pathogenic mechanism that underlies amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disorder that lacks disease modifying therapies. We previously developed a mouse model in which TDP-43 is selectively deleted from motor neurons (ChAT-Cre;Tardbpf/f) that mimics the early stages of ALS. Here, we demonstrate that intravenous delivery of a blood-brain-barrier (BBB) permeable AAV capsid expressing our rationally designed splicing repressor CTR (AAV-PHP.eB-CTR) in symptomatic ChAT-Cre;Tardbpf/f mice markedly slowed disease progression and prevented paralysis. Systemic delivery of AAV-PHP.eB-CTR led to transduction of [~]80% of spinal motor neurons, repression of TDP-43-associated cryptic exons within motor neurons expressing CTR, and attenuation of motor neuron loss. Notably, the addition of the TARDBP 3UTR autoregulatory element to CTR maintained its expression within a physiological range. In control littermates that received AAV-PHP.eB-CTR and were monitored for >20 months, grip strength and body weight remained normal, and no histopathological abnormalities were observed, underscoring a favorable safety profile for this gene therapy. These results provide preclinical proof-of-concept that BBB-crossing AAV delivery of CTR can rescue motor neuron disease through the restoration of TDP-43 function, offering a promising mechanism-based therapeutic strategy for ALS.

neuroscience↗