Laurie Sanders

Lewy body disorders are characterized by oxidative damage to DNA and inclusions rich in aggregated forms of α-synuclein. Among other roles, apurinic/apyrimidinic endonuclease 1 (APE1) repairs oxidative DNA damage, and APE1 polymorphisms have been linked to cases of Lewy body disorders. However, the link between APE1 and α-synuclein is unexplored. We report that knockdown or inhibition of APE1 amplified inclusion formation in primary hippocampal cultures challenged with preformed α-synuclein fibrils. Fibril infusions into the mouse olfactory bulb/anterior olfactory nucleus (OB/AON) elicited a modest decrease in APE1 expression in the brains of male mice but an increase in females. Similarly, men with Lewy body disorders displayed lower APE1 expression in the OB and amygdala compared to women. Preformed fibril infusions of the mouse OB/AON induced more robust base excision repair of DNA lesions in females than males. No fibril-mediated loss of APE1 expression was observed in male mice when the antioxidant N-acetylcysteine was added to their diet. These findings reveal a potential sex-biased link between α-synucleinopathy and APE1 in mice and humans. Further studies are warranted to determine how this multifunctional protein modifies α-synuclein inclusions and, conversely, how α-synucleinopathy and biological sex interact to modify APE1.

Lewy body disorders are characterized by proteostatic and redox disequilibrium, leading to deposition of α-synuclein in hallmark inclusions and oxidative damage to DNA. One common pathway for repair of oxidative DNA damage is base excision repair (BER), which involves the coordinated activity of several enzymes, including apurinic/apyrimidinic endonuclease 1 (APE1). The main goal of this study was to assess APE1 in rodents and humans with α-synucleinopathy, and to test the functional impact of APE1 in the preformed α-synuclein fibril model. First, we report that knockdown of APE1 with two independent shRNA sequences or inhibition of APE1 DNA repair activity increased inclusions bearing pathologically-phosphorylated α-synuclein (pSer129) in preformed fibril-treated primary hippocampal cultures. Second, we examined APE1 expression in a mouse model of limbic-centered α-synucleinopathy, in which α-synuclein fibrils are infused into the olfactory bulb/anterior olfactory nucleus (OB/AON). Six months later, we observed a fibril-induced decrease in APE1 expression in the brains of male mice and an increase in females. Similar sex-opposing patterns were noted for APE1 mRNA expression. Third, we demonstrated that the loss of APE1 in fibril-infused male mice in vivo is mediated by oxidative stress, as APE1 loss was abolished by dietary administration of the antioxidant N-acetylcysteine. Fourth, OB/AON tissues harvested from fibril-infused male mice displayed higher cleavage of synthetic DNA lesions on a biochip than tissues collected in parallel from fibril-infused female mice. However, OB/AON tissues harvested from fibril-infused female mice had higher DNA repair activity compared to males. Assessments of open field activity measures and sucrose preference revealed a negative behavioral impact of α-synuclein fibril infusions in male but not female mice. Fifth, men with Lewy body disorders displayed lower APE1 expression in the OB and amygdala compared to women with Lewy body disorders, similar to fibril-infused mice. Finally, we infused α-synuclein fibrils into the OB/AON of transgenic APE1 overexpressing rats and observed a reduction in pSer129 levels in male and female brains compared to fibril-infused wildtype rats. Preliminary data suggest that APE1 overexpression in fibril-infused rats improved olfaction and anxiety measures, especially in males. These findings reveal a sex-biased impact of limbic α-synucleinopathy on APE1 expression and function but also suggest that APE1 overexpression attenuates α-synucleinopathy in both sexes.

Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative brain disorder that affects tens of millions of older adults worldwide and has significant economic and societal impacts. Despite its prevalence and severity, early diagnosis of AD remains a considerable challenge. Here we report an integrated acoustofluidics-based diagnostic system (ADx), which combines triple functions of acoustics, microfluidics, and orthogonal biosensors for clinically accurate, sensitive, and rapid detection of AD biomarkers from human plasma. We design and fabricate a surface acoustic wave-based acoustofluidic separation device to isolate and purify AD biomarkers to increase the signal-to-noise ratio. Multimodal biosensors within the integrated ADx are fabricated by in-situ patterning of the ZnO nanorod array and deposition of Ag nanoparticles onto the ZnO nanorods for surface-enhanced Raman scattering (SERS) and electrochemical immunosensors. We obtain the label-free detections of SERS and electrochemical immunoassay of clinical plasma samples from AD patients and healthy controls with high sensitivity and specificity. We believe that this efficient integration provides promising solutions for the early diagnosis of AD.

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most common cause of familial Parkinson disease. Although LRRK2-related Parkinson disease patients have a heightened risk of certain nonskin cancers, including breast cancer, it is unknown whether LRRK2 somatic mutations occur and are associated with breast cancer. The objective of this study was to evaluate the occurrence of LRRK2 somatic mutations in breast cancer and the clinicopathologic features associated with LRRK2-mutated tumors. Using The Cancer Genome Atlas Breast Cancer Project, somatic LRRK2 DNA sequence information was obtained for 93 cases, of which 17 cases (18%) with 18 mutations were identified. LRRK2-mutated mammary carcinomas are enriched with stop-gain, truncating mutations predicted to result in loss of function; missense mutations frequently targeted the GTPase and kinase domains. Tumors displayed predominantly high-grade morphology with abundant granular eosinophilic cytoplasm, resembling mitochondria-rich apocrine-like carcinomas. Exploration of the genomic landscape of LRRK2-mutated carcinomas yielded frequent TP53 deactivation and a remarkably high tumor mutation burden. More important, breast cancers with LRRK2 mutations are associated with reduced patient survival compared with The Cancer Genome Atlas Breast Cancer Project cohort. These findings, for the first time, show that somatic LRRK2 mutations occur frequently in breast cancer, and the high mutation burden seen in this subset of tumors suggests that LRRK2 mutations may herald benefit from immune checkpoint inhibition.