Summary Mutations in α-synuclein and Leucine-rich repeat kinase 2 (LRRK2) are linked to autosomal dominant forms of Parkinson’s disease (PD). However, little is known about any potential pathophysiological interplay between these two PD-related genes. Here we show in transgenic mice that although over-expression of LRRK2 alone did not cause neurodegeneration, the presence of excess LRRK2 greatly accelerated the progression of neuropathological abnormalities developed in PD-related A53T α-synuclein transgenic mice. Moreover, we found that LRRK2 promoted the abnormal aggregation and somatic accumulation of α-synuclein in A53T mice, likely resulted from the impairment of microtubule dynamics, Golgi organization, and ubiquitin-proteasome pathway. Conversely, genetic ablation of LRRK2 preserved the Golgi structure, suppressed the aggregation and somatic accumulation of α-synuclein, and thereby delayed the progression of neuropathology in A53T mice. These findings demonstrate that over-expression of LRRK2 enhances α-synuclein-mediated cytotoxicity and suggest inhibition of LRRK2 expression as a potential therapeutic option for ameliorating α-synuclein-induced neurodegeneration.

High-throughput proteomic profiling using antibody or aptamer-based affinity reagents is used increasingly in human studies. However, direct analyses to address the relative strengths and weaknesses of these platforms are lacking. We assessed findings from the SomaScan1.3K ( N = 1301 reagents), the SomaScan5K platform ( N = 4979 reagents), and the Olink Explore ( N = 1472 reagents) profiling techniques in 568 adults from the Jackson Heart Study and 219 participants in the HERITAGE Family Study across four performance domains: precision, accuracy, analytic breadth, and phenotypic associations leveraging detailed clinical phenotyping and genetic data. Across these studies, we show evidence supporting more reliable protein target specificity and a higher number of phenotypic associations for the Olink platform, while the Soma platforms benefit from greater measurement precision and analytic breadth across the proteome.

The persistent increase in the worldwide burden of type 2 diabetes mellitus (T2D) and the accompanying rise of its complications, including cardiovascular disease, necessitates our understanding of the metabolic disturbances that cause diabetes mellitus. Metabolomics and proteomics, facilitated by recent advances in high-throughput technologies, have given us unprecedented insight into circulating biomarkers of T2D even over a decade before overt disease. These markers may be effective tools for diabetes mellitus screening, diagnosis, and prognosis. As participants of metabolic pathways, metabolite and protein markers may also highlight pathways involved in T2D development. The integration of metabolomics and proteomics with genomics in multiomics strategies provides an analytical method that can begin to decipher causal associations. These methods are not without their limitations; however, with careful study design and sample handling, these methods represent powerful scientific tools that can be leveraged for the study of T2D. In this article, we aim to give a timely overview of circulating metabolomics and proteomics findings with T2D observed in large human population studies to provide the reader with a snapshot into these emerging fields of research.

Background: Plasma proteins are critical mediators of cardiovascular processes and are the targets of many drugs. Previous efforts to characterize the genetic architecture of the plasma proteome have been limited by a focus on individuals of European descent and leveraged genotyping arrays and imputation. Here we describe whole genome sequence analysis of the plasma proteome in individuals with greater African ancestry, increasing our power to identify novel genetic determinants. Methods: Proteomic profiling of 1,301 proteins was performed in 1852 Black adults from the Jackson Heart Study using aptamer-based proteomics (SomaScan ® ). Whole genome sequencing association analysis was ascertained for all variants with minor allele count ≥ 5. Results were validated using an alternative, antibody-based, proteomic platform (Olink ® ) as well as replicated in the Multi-Ethnic Study of Atherosclerosis and the HERITAGE Family Study. Results: We identify 569 genetic associations between 479 proteins and 438 unique genetic regions at a Bonferroni-adjusted significance level of 3.8 × 10 −11 . These associations include 114 novel locus-protein relationships and an additional 217 novel sentinel variant-protein relationships. Novel cardiovascular findings include new protein associations at the APOE gene locus including ZAP70 (sentinel single nucleotide polymorphism [SNP] rs7412-T, β = 0.61±0.05, p-value = 3.27 × 10 −30 ) and MMP-3 (β = -0.60±0.05, p = 1.67 × 10 −32 ), as well as a completely novel pleiotropic locus at the HPX gene, associated with nine proteins. Further, the associations suggest new mechanisms of genetically mediated cardiovascular disease linked to African ancestry; we identify a novel association between variants linked to APOL1 associated chronic kidney and heart disease and the protein CKAP2 (rs73885319-G, β = 0.34±0.04, p = 1.34 × 10 −17 ) as well as an association between ATTR amyloidosis and RBP4 levels in community dwelling individuals without heart failure. Conclusions: Taken together, these results provide evidence for the functional importance of variants in non-European populations, and suggest new biological mechanisms for ancestry-specific determinants of lipids, coagulation and myocardial function.