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Madhavan, L.

Publications and source records attributed to Madhavan, L..

3 recordsLinked to original sources

The 5-HT1F Receptor Agonist Lasmiditan improves Cognition and Ameliorates Associated Cortico-Hippocampal Pathology in Aging Parkinsonian Mice

While the etiopathology of Parkinsons disease (PD) is complex, mitochondrial dysfunction is established to have a central role. Thus, mitochondria have emerged as targets of therapeutic interventions aiming to slow or modify PD progression. We have previously identified serotonergic 5-HT1F receptors as novel mediators of mitochondrial biogenesis (MB) - the process of producing new mitochondria. Given this, here, we assessed the therapeutic potential of the FDA-approved 5-HT1F receptor agonist, lasmiditan, in a chronic progressive PD model (Thy1-aSyn line 61 mice). It was observed that systemic lasmiditan exhibited robust brain penetration and reversed cognitive deficits in young (4-5.5 months old) Thy1-aSyn mice (1mg/kg, every other day). Anxiety-like behavior was also improved while motor function remained unaffected. These behavioral changes were associated with enhanced MB and mitochondrial function, paired with reduced alpha-synuclein aggregation particularly in cortico-hippocampal regions. Furthermore, in older (10-11.5 months old) mice, although the effects were milder, daily lasmiditan administration increased MB and bettered cognitive abilities. In essence, these findings indicate that repurposing lasmiditan could be a potent strategy to address PD-related cognitive decline.

neuroscience↗

Parallel Neurodegenerative Phenotypes in Sporadic Parkinsons Disease Fibroblasts and Midbrain Dopamine Neurons

Understanding the mechanisms causing Parkinsons disease (PD) is vital to the development of much needed early diagnostics and therapeutics for this debilitating condition. Here, we report cellular and molecular alterations in skin fibroblasts of late-onset sporadic PD subjects, that were recapitulated in matched induced pluripotent stem cell (iPSC)-derived midbrain dopamine (DA) neurons, reprogrammed from the same fibroblasts. Specific changes in growth, morphology, reactive oxygen species levels, mitochondrial function, and autophagy, were seen in both the PD fibroblasts and DA neurons, as compared to their respective controls. Additionally, significant alterations in alpha synuclein expression and electrical activity were also noted in the PD DA neurons. Interestingly, although the fibroblast and neuronal phenotypes were similar to each other, they also differed in their nature and scale. Furthermore, statistical analysis revealed novel associations between various clinical measures of the PD subjects and the different fibroblast and neuronal data. In essence, these findings encapsulate spontaneous, in-tandem, disease-related phenotypes in both sporadic PD fibroblasts and iPSC-based DA neurons, from the same patient, and generates an innovative model to investigate PD mechanisms with a view towards rational disease stratification and precision treatments.

neuroscience↗

α-synuclein over expression, NRF2 suppression, and enhanced ferroptosis creates a vicious cycle of neuronal loss in Parkinson's disease

Parkinsons disease (PD) is the second most common neurodegenerative disorder, affecting millions each year. Most PD cases ([~]90%) are sporadic, resulting from the age-dependent accumulation of pathogenic effects. One key pathological hallmark of PD progression is the accumulation of alpha-synuclein (-syn), which has been shown to negatively affect neuronal function and viability. Here, using 3- and 6-month-old Nrf2+/+ and Nrf2-/- mice overexpressing human -syn (PD model), we show that loss of NRF2 increases markers of ferroptosis across PD-relevant brain regions. Increased ferroptosis was associated with an age- and genotype-dependent increase in -syn pathology and behavioral deficits. Finally, we demonstrate that -syn overexpression sensitizes neuronal cells and ex vivo brain slices to ferroptosis induction, which may be due to -syn suppression of NRF2 at the protein level. Altogether, these results indicate that NRF2 is a critical anti-ferroptotic mediator of neuronal survival, and that the vicious cycle of -syn overexpression and NRF2 suppression, leading to enhanced neuronal ferroptotic cell death, could represent a targetable and currently untapped means of preventing PD onset and progression.

neuroscience↗