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Biology subjects

Camp, N. D.

Publications and source records attributed to Camp, N. D..

4 recordsLinked to original sources

An integrated, scaled approach to resolve TSC2 variants of uncertain significance

Obtaining a precise genetic tuberous sclerosis diagnosis is a challenge as many missense TSC2 variants are variants of uncertain significance (VUS). VUS in TSC2 have been resolved by one-at-a-time functional assays, but these assays cannot scale to the 3,634 TSC2 missense VUS observed so far. To address this challenge, we used massively parallel sequencing to measure the steady-state abundance of almost 9,000 TSC2 missense variants and developed an mTOR pathway activity assay using genome editing and cell sorting to generate activity scores for 391 missense variants. 1,288 of 8,891 (14.49%) missense variants assayed had altered TSC2 abundance, and 69 of 391 (17.65%) missense variants assayed had altered mTOR pathway activity. Calibration and integration of these data into classification of variants identified in a clinical cohort putatively reclassified 212 of 276 (76.8%) TSC2 missense VUS. These datasets will lead to improved genetic diagnosis of tuberous sclerosis with potential positive impacts on the clinical management of patients and their families.

genetics↗

Humanized mice enable in vivo evaluation of engineered plasma cell biology and therapeutic function

Engineered plasma cells (ePCs) offer a durable strategy for in vivo delivery of therapeutic antibodies, but standard immunodeficient mouse models lack human immune factors critical for plasma cell survival and function. We utilized a humanized mouse model in which NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice were engrafted with human CD34+ stem cells as recipients for infusions with autologous ePCs. In this setting, ePCs localized to plasma cell niches and stably secreted antibodies for over three months. To improve the selection of antibodies for secretion, we developed a B cell receptor surface display screen that identified candidate antibody sequences with high secretion potential. An anti-SARS-CoV-2 antibody (clone 297) selected by this method showed robust secretion both in vitro and vivo, and serum from ePC-engrafted mice potently neutralized SARS-CoV-2 pseudovirus. Together, these findings establish a physiologically relevant model for testing human ePCs, and offer a generalizable strategy for optimizing antibody selection to support long-term therapeutic delivery.

molecular biology↗

Functional Maturation of Human iPSC-based Cardiac Microphysiological Systems with Tunable Electroconductive Decellularized Extracellular Matrices

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) offer tremendous potential for use in engineering human tissues for regenerative therapy and drug screening. However, differentiated cardiomyocytes are phenotypically immature, reducing assay reliability when translating in vitro results to clinical studies and precluding hiPSC-derived cardiac tissues from therapeutic use in vivo. To address this, we have developed hybrid hydrogels comprised of decellularized porcine myocardial extracellular matrix (dECM) and reduced graphene oxide (rGO) to provide a more instructive microenvironment for proper cellular and tissue development. A tissue-specific protein profile was preserved post-decellularization, and through the modulation of rGO content and degree of reduction, the mechanical and electrical properties of the hydrogels could be tuned. Engineered heart tissues (EHTs) generated using dECM-rGO hydrogel scaffolds and hiPSC-derived cardiomyocytes exhibited significantly increased twitch forces at 14 days of culture and had increased the expression of genes that regulate contractile function. Similar improvements in various aspects of electrophysiological function, such as calcium-handling, action potential duration, and conduction velocity, were also induced by the hybrid biomaterial. We also demonstrate that dECM-rGO hydrogels can be used as a bioink to print cardiac tissues in a high-throughput manner, and these tissues were utilized to assess the proarrhythmic potential of cisapride. Action potential prolongation and beat interval irregularities was observed in dECM-rGO tissues at clinical doses of cisapride, indicating that the enhanced maturation of these tissues corresponded well with a capability to produce physiologically relevant drug responses.

bioengineering↗

Synthesizing Signaling Pathways from Temporal Phosphoproteomic Data

Advances in proteomics reveal that pathway databases fail to capture the majority of cellular signaling activity. Our mass spectrometry study of the dynamic epidermal growth factor (EGF) response demonstrates that over 89% of significantly (de)phosphorylated proteins are excluded from individual EGF signaling maps, and 63% are absent from all annotated pathways. We present a computational method, the Temporal Pathway Synthesizer (TPS), to discover missing pathway elements by modeling temporal phosphoproteomic data. TPS uses constraint solving to exhaustively explore all possible structures for a signaling pathway, eliminating structures that are inconsistent with protein-protein interactions or the observed phosphorylation event timing. Applied to our EGF response data, TPS connects 83% of the responding proteins to receptors and signaling proteins in EGF pathway maps. Inhibiting predicted active kinases supports the TPS pathway model. The TPS algorithm is broadly applicable and also recovers an accurate model of the yeast osmotic stress response.

bioinformatics↗