Temporal lobe epilepsy (TLE) causes a variety of symptoms, with memory impairment affecting 70 to 80% of individuals and serving as a primary comorbidity that significantly impacts quality of life. The underlying mechanisms related to the emergence of memory deficits disrupting cognitive function remain insufficiently studied, resulting in limited treatment options for memory deficits. To investigate the pathological mechanisms underlying memory impairment in TLE, we applied a transcriptomic approach by performing single-nuclei RNA sequencing on dorsal hippocampal tissue collected from pilocarpine-treated mice with TLE-like seizures and control mice. Nuclei were isolated from the tissue to profile cell-specific gene expression, focusing on microglia populations. We used RNAscope to detect microglial mRNA expression and immunohistochemistry to assess microglia morphology. Bioinformatic analysis was used to assess the activation state of the microglia and quantify expression levels of our genes of interest. Results revealed a distinct subset of microglia present in epileptic tissue but absent in controls, suggesting a potential link to cognitive dysfunction. Notably, microglia with lower ramification tended to express higher levels of mRNA from genes known to be upregulated in disease-activated microglia. We are currently validating these populations in vivo to better understand how they may contribute to memory impairment and serve as potential therapeutic targets in TLE.

Huntington’s Disease (HD) is a progressive neurodegenerative disorder caused by an expanded CAG trinucleotide repeat in the HTT gene on chromosome 4. FAN1 (Fanconi-associated nuclease 1) is a DNA repair gene implicated in modulating the age of symptom onset in HD. In this study, we investigated how alterations in FAN1 expression affect circadian locomotor activity in the Q140 knock-in mouse model of HD. We used three genetically modified FAN1 mouse lines: FAN1 knock-in (KI), knock-down (KD), and Bacterial Artificial Chromosome (BAC) overexpression. For each line, four genotypes were examined: wild-type, Q140, FAN1-KI/KD/BAC, and the corresponding FAN1-modified Q140 compound mice. Locomotor activity was monitored between 9 and 12 months of age, with analyses focused on the final 10 days of recording. Circadian activity patterns were quantified using ClockLab and Nitecap software to assess parameters such as rhythmicity, period, and amplitude, and to visualize individual and group-level differences. Our findings show that reduced FAN1 expression exacerbates disruptions in circadian locomotor rhythms, while FAN1 overexpression ameliorates these deficits in Q140 mice. Specifically, FAN1 overexpression delays the decline in rhythmicity and amplitude, suggesting a protective effect on circadian function and potentially on disease onset. These results highlight a novel role for FAN1 in maintaining circadian rhythmicity in HD and support further investigation into FAN1-modulating therapies.

The U.S.A. faces a chronic pain epidemic, impacting ~20% of Americans. Poorly managed pain treatments increase vulnerability to opioid misuse and substance use disorders. To improve pain management strategies, it is critical to identify the specific neuronal circuits that are responsible for chronic pain-related behaviors. The claustrum (CLA) is a small longitudinal brain structure that regulates cortical activity. Acute noxious stimuli modulate CLA activity. Further, reduced CLA activity drives binge consumption of sucrose rewards. While inflammatory pain increases dynorphin-kappa opioid receptor (KOR) signaling in many brain regions, little is known about how dynorphin-KOR signaling impacts CLA activity. Interestingly, KORs are highly expressed in the CLA. This study investigates whether inflammatory pain alters consumption of sucrose reward, how acute noxious stimuli impact CLA activity, and the role of KORs in pain-induced binge consumption. To test this, a combination of behavioral pharmacology, fiber photometry, and in situ hybridization was used. Lastly, the CLA’s projections to the anterior cingulate cortex (ACC)—a structure involved in integrating the emotional components of pain—were evaluated using optogenetic approaches. Together, these results uncover a novel behavioral outcome associated with the persistent pain experience and identify the CLA as a potential key player in mediating these responses.

Like humans, zebra finches engage in vocal learning, key to social interactions. Human mutations in the Zeb2 transcription factor cause Mowat-Wilson Syndrome, characterized by speech impairments. Here, we use zebra finches to understand Zeb2’s function in vocal learning based on similar timelines for vocal development and underlying cortical circuitry. Unlike humans, only male zebra finches learn to sing. HVC (proper name) is the vocal premotor cortical nucleus that projects to the robust nucleus of the arcopallium (RA), the primary cortical nucleus, similar to human intracortical connections controlling speech. Male vocal learning includes a sensory phase (~25–65 days; d) and a sensorimotor phase (~35–100d) when juveniles refine their songs, mirroring phases for human language acquisition. Sensorimotor onset coincides with HVC innervation of RA suggesting that this intra-cortical connection triggers vocal babbling. We previously showed that Zeb2 is globally expressed in hatchling brains. By 25d however, Zeb2 is downregulated in females, while males retain elevated HVC expression. At ~35d, HVC projections toward RA retract in females. We hypothesize that this difference underlies the behavioral sexual dimorphism. Currently, I am reanalyzing Zeb2 expression in HVC at 25d using brains of previously collected birds. I will supplement adult male findings by conducting perfusions, cryosectioning, immunohistochemistry, and analysis. My work aims to clarify Zeb2’s role in vocal learning circuit formation and maintenance.

Alzheimer’s Disease (AD) affects about 6.7 million Americans and is characterized by progressive cognitive decline, synaptic loss, and neuroinflammation driven by reactive astrocytes. Sex is a known risk factor for AD, but its role in disease progression remains unclear. We used the humanized AD model, App(NL-F)—which expresses wildtype APP but produces pathogenic amyloid beta—to investigate the interactive effects of sex, age, and disease on spatial reference memory, hippocampal astrocytes and synapses, and cholesterol metabolism. Dorsal hippocampus-dependent water maze testing revealed that midlife AD males had significantly impaired spatial reference memory compared to age-matched wildtype (WT) males, App(NL-F) females, and young App(NL-F) males. Immunostaining and confocal imaging in the CA1 and dentate gyrus of the dorsal hippocampus showed increased reactive astrocytes and synaptic loss exclusively in midlife AD males. Previous findings report reduced cholesterol expression in AD brains and aging astrocytes. Given that cholesterol plays a crucial role in synaptic regulation and is synthesized by astrocytes, we examined FDPS, a critical enzyme in cholesterol biosynthesis. Our analysis demonstrated decreased FDPS expression in reactive astrocytes from midlife AD males. These findings highlight the potential of targeting FDPS in the cholesterol biosynthesis pathway as a novel therapeutic approach for AD in midlife males.